Glycoside compound, method for producing thioether, ether, method for producing ether, method for producing glycoside compound, method for producing nucleic acid

ABSTRACT

The invention provides a glucoside compound, which is capable of providing a phosphoramidite, which can be produced at low cost and can produce a nucleic acid in high yield and with high purity. The glycoside compound has the formula 
                         
wherein B, R 1 , and R 2  are as described herein, R 3  is —OCH 2 (OCH 2 ) n —O-L 1 -[D 1 ], in which L 1  is an ethylene group, wherein hydrogen atoms besides a hydrogen atom bonded to the α-position relative to [D 1 ] are optionally substituted by a straight chain or branched alkyl group, n is a positive integer, and [D 1 ] is an electron-withdrawing group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is the U.S. national phase of InternationalPatent Application No. PCT/JP2012/071517, filed Aug. 24, 2012, whichclaims the benefit of Japanese Patent Application No. 2011-184196, filedon Aug. 25, 2011, which are incorporated by reference in theirentireties herein.

INCORPORATION-BY-REFERENCE OF MATERIAL ELECTRONICALLY SUBMITTED

Incorporated by reference in its entirety herein is a computer-readablenucleotide/amino acid sequence listing submitted concurrently herewithand identified as follows: 1,354 bytes ASCII (Text) file named“713609SequenceListing.txt,” created Feb. 21, 2014.

TECHNICAL FIELD

The present invention relates to a glycoside compound, a productionmethod of thioether, ether, a production method of ether, a productionmethod of glycoside compound, and a production method of nucleic acid.

BACKGROUND ART

As a production (synthesis) method of nucleic acids such as DNA, RNA andthe like, for example, a phosphoramidite method and the like are used.As a starting material for the nucleic acid synthesis by thephosphoramidite method, phosphoramidite of nucleoside (hereinafter to besimply referred to as “phosphoramidite”) is used. Examples of theprotecting group at the 2′-position of the aforementionedphosphoramidite include many protecting groups such as TBDMS(tert-butyldimethylsilyl) group, TOM (triisopropylsilyloxymethyl) group,ACE (bis(2-acetoxyethoxy)methyl) group and the like. As for TOM amidite,it is described in, for example, the following non-patent document 1 andthe like.

DOCUMENT LIST Non-Patent Document

Non-Patent Document 1:

-   http://www.glenresearch.com/Technical/TB_RNA_TOM_Deprotection.pdf    (searched on Aug. 18, 2011)

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, since the production cost of conventional phosphoramidites suchas TOM amidite, ACE amidite and the like is high, they are notconvenient as starting materials for the synthesis of pharmaceuticalproducts and the like. In addition, the yield and purity of nucleic acidare sometimes not very high when nucleic acid is synthesized by acoupling (condensation) reaction using TBDMS amidite.

Therefore, the present invention aims to provide a glycoside compound, aproduction method of thioether, ether, a production method of ether, anda production method of a glycoside compound, which are capable ofproviding a phosphoramidite which can be produced at a low cost and canproduce a nucleic acid in a high yield and with high purity.Furthermore, the present invention aims to provide a production methodof a nucleic acid, which can produce a nucleic acid in a high yield andwith high purity by using the aforementioned phosphoramidite.

Means of Solving the Problems

To achieve the aforementioned object, the glycoside compound of thepresent invention is

a glycoside compound represented by the following chemical formula (1),an enantiomer thereof, a tautomer or stereoisomer thereof or a saltthereof:

In the aforementioned chemical formula (1),

B is an atomic group having a nucleic acid base skeleton, and optionallyhaving a protecting group,

R¹ and R² are each a hydrogen atom or a protecting group,

or R¹ and R² in conjunction optionally form an atomic group representedby the following chemical formula (R¹R²A) or R¹R²B)

each R^(1a) is a hydrogen atom, a straight chain or branched alkylgroup, or a straight chain or branched alkoxy group, which may be thesame or different,

R³ is a group represented by the following chemical formula (R³):

in the aforementioned chemical formula (R³),

L¹ is an ethylene group (—CH₂CH₂—), wherein hydrogen atoms besides ahydrogen atom bonded to the α-position relative to [D¹] are optionallysubstituted by a straight chain or branched alkyl group,

n is a positive integer, and

[D¹] is an electron-withdrawing group.

The first production method of thioether in the present inventionincludes

a coupling reaction of thiol or thioalkoxide represented by thefollowing chemical formulas (101a) and (101b) with a halide representedby the following chemical formula (102) to give a thioether representedby the following chemical formula (103).

In the aforementioned chemical formulas (101a), (101b) and (103),

R⁴ and R⁵ are each a hydrocarbon group, a straight chain or branchedalkyl group, a straight chain or branched alkenyl group, a straightchain or branched alkynyl group, an aryl group, a straight chain orbranched arylalkyl group, a cycloalkyl group, a cycloalkenyl group, astraight chain or branched cycloalkylalkyl group, a straight chain orbranched cyclylalkyl group, or a straight chain or branched alkoxyalkylgroup, which may be the same or different,

in the aforementioned chemical formulas (101a) and (101b),

M¹ and M² may be the same or different and each is a hydrogen atom or ametal,

in the aforementioned chemical formulas (102) and (103),

n is a positive integer, and

in the aforementioned chemical formula (102),

X¹ and X² may be the same or different and each is halogen.

The second production method of thioether in the present inventionincludes

a coupling reaction of a thioether represented by the following chemicalformula (103b) and an alcohol represented by the following chemicalformula (104), in the presence of a halogenating agent and a Lewis acidto give a thioether represented by the following chemical formula (103).

In the aforementioned chemical formulas (103b), (104) and (103),

R⁴, R⁵ and R⁶ are each a hydrocarbon group, a straight chain or branchedalkyl group, a straight chain or branched alkenyl group, a straightchain or branched alkynyl group, an aryl group, a straight chain orbranched arylalkyl group, a cycloalkyl group, a cycloalkenyl group, astraight chain or branched cycloalkylalkyl group, a straight chain orbranched cyclylalkyl group, or a straight chain or branched alkoxyalkylgroup, which may be the same or different, and

in the aforementioned chemical formulas (103b) and (103),

n is an integer of two or more.

The ether in the present invention is

an ether represented by the following chemical formula (106), anenantiomer thereof, a tautomer or stereoisomer thereof or a saltthereof.

In the aforementioned chemical formula (106),

R⁴ is a hydrocarbon group, a straight chain or branched alkyl group, astraight chain or branched alkenyl group, a straight chain or branchedalkynyl group, an aryl group, a straight chain or branched arylalkylgroup, a cycloalkyl group, a cycloalkenyl group, a straight chain orbranched cycloalkylalkyl group, a straight chain or branched cyclylalkylgroup, or a straight chain or branched alkoxyalkyl group,

n is a positive integer,

L¹ is an ethylene group (—CH₂CH₂—), wherein hydrogen atoms besides ahydrogen atom bonded to the α-position relative to [D¹] are optionallysubstituted by a straight chain or branched alkyl group, and

[D¹] is an electron-withdrawing group.

The production method of the ether in the present invention includes

a coupling reaction of a thioether represented by the following chemicalformula (103) and an alcohol represented by the following chemicalformula (105), in the presence of a halogenating agent and a Lewis acidto give the aforementioned ether in the present invention.

In the aforementioned chemical formulas (103) and (105),

R⁴ is as defined for the aforementioned chemical formula (106),

R⁵ is a hydrocarbon group, a straight chain or branched alkyl group, astraight chain or branched alkenyl group, a straight chain or branchedalkynyl group, an aryl group, a straight chain or branched arylalkylgroup, a cycloalkyl group, a cycloalkenyl group, a straight chain orbranched cycloalkylalkyl group, a straight chain or branched cyclylalkylgroup, or a straight chain or branched alkoxyalkyl group, which may bethe same as or different from R⁴,

in the aforementioned chemical formula (103),

n is as defined for the aforementioned chemical formula (106), and

in the aforementioned chemical formula (105),

L¹ and [D¹] are as defined for the aforementioned chemical formula(106).

The production method of the glycoside compound in the present inventionis a production method of the aforementioned glycoside compound of thepresent invention, an enantiomer thereof, a tautomer or stereoisomerthereof or a salt thereof,

which includes a coupling step including a coupling reaction of aglycoside compound represented by the following chemical formula (107)and an ether represented by the following chemical formula (106), in thepresence of a halogenating agent and a Lewis acid to give a glycosidecompound represented by the following chemical formula (1a),

wherein the glycoside compound represented by the following chemicalformula (1a) is the glycoside compound which is a glycoside compoundwherein R¹ and R² in the aforementioned chemical formula (1) inconjunction form an atomic group represented by the aforementionedchemical formula (R¹R²A) or (R¹R²B).

In the aforementioned chemical formulas (107) and (1a),

L² is an atomic group represented by the aforementioned chemical formula(R¹R²A) or (R¹R²B),

B is as defined for the aforementioned chemical formula (1),

in the aforementioned chemical formula (106),

R⁴ is a hydrocarbon group, a straight chain or branched alkyl group, astraight chain or branched alkenyl group, a straight chain or branchedalkynyl group, an aryl group, a straight chain or branched arylalkylgroup, a cycloalkyl group, a cycloalkenyl group, a straight chain orbranched cycloalkylalkyl group, a straight chain or branched cyclylalkylgroup, or a straight chain or branched alkoxyalkyl group, and

in the aforementioned chemical formulas (106) and (1a),

L¹, n and [D¹] are as defined for the aforementioned chemical formula(1).

The production method of a nucleic acid in the present invention is aproduction method of a nucleic acid having the structure represented bythe following chemical formula (I), and is characterized by including acondensation step for condensing the glycoside compound of the presentinvention wherein the glycoside compound represented by theaforementioned chemical formula (1) is the glycoside compoundrepresented by the aforementioned chemical formula (2).

In the aforementioned chemical formula (I), B is as defined for theaforementioned chemical formula (1),

R¹⁰⁰ is a hydrogen atom or a hydroxyl group,

respective B may be the same or different, and respective R¹⁰⁰ may bethe same or different,

m is a positive integer.

In the aforementioned chemical formula (2),

B, R¹ and R³ are as defined for the aforementioned chemical formula (1),

provided that R¹ is a protecting group,

R^(2a) and R^(2b) may be the same or different and each is a hydrogenatom or any substituent,

or R^(2a) and R^(2b) optionally form a nonaromatic ring, in conjunctionwith a nitrogen atom to which they are bonded, the aforementionednonaromatic ring optionally has a nitrogen atom, an oxygen atom or asulfur atom, besides the aforementioned nitrogen atom, and optionallyhas a substituent, and

R^(2c) is a hydrogen atom, an electron-withdrawing group or anysubstituent, which may be optionally substituted by anelectron-withdrawing group [D²].

Effect of the Invention

According to the glycoside compound, the production method of thioether,ether, the production method of ether, and the production method of aglycoside compound, of the present invention, phosphoramidite that canbe produced at a low cost and can produce a nucleic acid in a high yieldand with high purity can be provided. Moreover, according to theproduction method of a nucleic acid in the present invention, a nucleicacid can be produced in a high yield and with high purity by using theaforementioned phosphoramidite.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an HPLC chart of the nucleic acid (before purification)produced in Example 6.

FIG. 2 is an HPLC chart of the nucleic acid (after purification)produced in Example 6.

FIG. 3 is a mass spectrum of the nucleic acid (after purification)produced in Example 6.

DESCRIPTION OF EMBODIMENTS

The present invention is explained in detail by way of Examples.However, the present invention is not limited by the followingexplanation.

Unless particularly specified, the terms used in the presentspecification can be used in the meanings generally adopted in thepertinent technical field.

According to the present invention, for example, one or more effectsfrom the following [1]-[5] can be obtained. However, these effects areexemplary and do not limit the present invention.

[1] Of the glycoside compounds represented by the aforementionedchemical formula (1) of the present invention, a glycoside compoundrepresented by the aforementioned chemical formula (2) (phosphoramidite)can be preferably used as a starting material for the synthesis ofnucleic acid. In the glycoside compound represented by theaforementioned chemical formula (2) (phosphoramidite), anelectron-withdrawing group [D¹] is farther from phosphate group than TOMamidite, ACE amidite and the like and the interaction between [D¹] andthe phosphate group is weak. Therefore, glycoside compound (2) is moreeasily synthesized than conventional amidites such as TOM amidite, ACEamidite and the like and can be obtained with high purity.[2] Since the glycoside compound of the present invention can beproduced at a lower cost than conventional ACE amidite, TOM amidite andthe like, it is suitable as a starting material of medicaments and thelike.[3] The thioether represented by the aforementioned chemical formula(103) and the ether represented by the aforementioned chemical formula(106), which are the synthesis intermediates for the glycoside compoundof the present invention, can be produced at a low cost, by producingaccording to the aforementioned production method of the presentinvention. Consequently, the glycoside compound of the present inventioncan be produced at a still lower cost.[4] Particularly, the thioether represented by the aforementionedchemical formula (103) is useful as a synthesis intermediate forpharmaceutical products, which is not only for the glycoside compound ofthe present invention. According to the aforementioned first and secondproduction methods of thioether in the present invention, the thioetherrepresented by the aforementioned chemical formula (103) can besynthesized in a higher yield and at a lower cost than in the past.[5] The production method of a nucleic acid in the present invention canproduce a nucleic acid with high purity and in a high yield by using theglycoside compound represented by the aforementioned chemical formula(2) (phosphoramidite) in the present invention. Specifically, forexample, it is also possible to synthesize RNA at a purity comparable tothat in DNA synthesis. While the reason therefor is not clear, forexample, improved efficiency of condensation reaction (couplingreaction) due to less steric hindrance during condensation reaction(coupling reaction) as compared to ACE amidite, TOM amidite and thelike, and the like are considered. In addition, the glycoside compoundrepresented by the aforementioned chemical formula (2) in the presentinvention permits easy deprotection in the condensation reaction(coupling reaction).1. Glycoside Compound

The glycoside compound of the present invention is, as mentioned above,

a glycoside compound represented by the following chemical formula (1),an enantiomer thereof, a tautomer or stereoisomer thereof or a saltthereof:

In the aforementioned chemical formula (1),

B is an atomic group having a nucleic acid base skeleton, and optionallyhaving a protecting group,

R¹ and R² are each a hydrogen atom or a protecting group,

or R¹ and R² in conjunction optionally form an atomic group representedby the following chemical formula (R¹R²A) or (R¹R²B):

each R^(1a) is a hydrogen atom, a straight chain or branched alkylgroup, or a straight chain or branched alkoxy group, which may be thesame or different,

R³ is a group represented by the following chemical formula (R³):

in the aforementioned chemical formula (R³),

L¹ is an ethylene group (—CH₂CH₂—), wherein hydrogen atoms besides ahydrogen atom bonded to the α-position relative to [D¹] are optionallysubstituted by a straight chain or branched alkyl group,

n is a positive integer, and

[D¹] is an electron-withdrawing group. Note that “bonded to theα-position relative to [D¹]” means being bonded to the same carbon atomto which [D¹] is bonded.

As the electron-withdrawing group [D¹] in the aforementioned chemicalformula (1), a cyano group, a nitro group, an alkylsulfonyl group,halogen, an arylsulfonyl group, a trihalomethyl group, or atrialkylamino group is preferable. The aforementioned trihalomethylgroup is, for example, a trichloromethyl group, a trifluoromethyl groupor the like. In the aforementioned chemical formula (1), theaforementioned straight chain or branched alkyl group for L¹ may be, forexample, a straight chain or branched alkyl group having 1-12 carbonatoms. L¹ is particularly preferably an unsubstituted ethylene group(—CH₂CH₂—). In the aforementioned chemical formula (1), n is notparticularly limited and, for example, within the range of 1-30,preferably 1-20.

In the aforementioned chemical formula (1), R¹ is, as mentioned above, ahydrogen atom or a protecting group. The protecting group R¹ is notparticularly limited and is, for example, a substituent represented byany of the following chemical formulas (R¹A), (R¹B), (R¹C) and (R¹D).

In the aforementioned chemical formula (R¹A),

R¹¹-R¹³ may be the same or different and each is a straight chain orbranched alkoxy group, or a straight chain or branched alkyl group, orabsent,

R¹¹-R¹³ are, when they are present, respectively present singly or inplurality, and when present in plurality, they may be the same ordifferent,

in the aforementioned chemical formula (R¹B),

R¹⁴-R¹⁶ may be the same or different and each is a hydrogen atom, astraight chain or branched alkyl group, or a straight chain or branchedalkoxy group,

in the aforementioned chemical formula (R¹C),

R¹⁷-R¹⁹ are each a hydrogen atom, halogen, a hydrocarbon group, astraight chain or branched alkyl group, a straight chain or branchedalkenyl group, a straight chain or branched alkynyl group, a straightchain or branched haloalkyl group, an aryl group, a heteroaryl group, astraight chain or branched arylalkyl group, a cycloalkyl group, acycloalkenyl group, a straight chain or branched cycloalkylalkyl group,a straight chain or branched cyclylalkyl group, a straight chain orbranched hydroxyalkyl group, a straight chain or branched alkoxyalkylgroup, a straight chain or branched aminoalkyl group, a straight chainor branched heterocyclylalkenyl group, a straight chain or branchedheterocyclylalkyl group, a straight chain or branched heteroarylalkylgroup, a silyl group, a silyloxyalkyl group, a mono-, di- ortrialkylsilyl group, or a mono-, di- or trialkylsilyloxyalkyl group,which may be the same or different,

in the aforementioned chemical formula (R¹D),

R²⁰-R²² may be the same or different and each is a hydrogen atom, or astraight chain or branched alkyl group.

In the aforementioned chemical formula (R¹A), preferably, R¹¹-R¹³ may bethe same or different and each is a straight chain or branched alkoxygroup having 1-12 carbon atoms, or a straight chain or branched alkylgroup having 1-12 carbon atoms, or absent. As mentioned above, R¹¹-R¹³are, when they are present, respectively present singly or in plurality,and when present in plurality, they may be the same or different. In theaforementioned chemical formula (R¹B), preferably, R¹⁴-R¹⁶ may be thesame or different and each is a hydrogen atom, a straight chain orbranched alkyl group having 1-12 carbon atoms, or a straight chain orbranched alkoxy group having 1-12 carbon atoms. In the aforementionedchemical formula (R¹C), preferably, R¹⁷-R¹⁹ are each a hydrogen atom,halogen, a straight chain or branched alkyl group having 1-12 carbonatoms, a straight chain or branched alkenyl group having 2-12 carbonatoms, a straight chain or branched alkynyl group having 2-12 carbonatoms, a straight chain or branched haloalkyl group having 1-12 carbonatoms, an aryl group having 5-24 carbon atoms, a heteroaryl group having5-24 carbon atoms, a straight chain or branched arylalkyl group having6-30 carbon atoms, a cycloalkyl group having 3-24 carbon atoms, acycloalkenyl group having 3-24 carbon atoms, a straight chain orbranched cycloalkylalkyl group having 4-30 carbon atoms, a straightchain or branched cyclylalkyl group having 4-30 carbon atoms, a straightchain or branched hydroxyalkyl group having 1-12 carbon atoms, astraight chain or branched alkoxyalkyl group having 1-12 carbon atoms, astraight chain or branched aminoalkyl group having 1-12 carbon atoms, astraight chain or branched heterocyclylalkenyl group having 5-30 carbonatoms, a straight chain or branched heterocyclylalkyl group having 4-30carbon atoms, a straight chain or branched heteroarylalkyl group having6-30 carbon atoms, a silyl group, a silyloxyalkyl group having 1-12carbon atoms, a mono-, di- or trialkylsilyl group having alkyl carbonnumber 1-12, or an alkyl group having 1-12 carbon atoms and substitutedby a mono-, di- or trialkylsilyloxy group having alkyl carbon number1-12, which may be the same or different. In the aforementioned chemicalformula (R¹D), preferably, R²⁰-R²² may be the same or different and eachis a hydrogen atom, or a straight chain or branched alkyl group having1-12 carbon atoms.

In the glycoside compound of the present invention, the substituentrepresented by the aforementioned chemical formula (R¹A) is preferably asubstituent represented by the following chemical formula (R¹A2)

In the aforementioned chemical formula (R¹A2),

R¹¹-R¹³ may be the same or different and each is a hydrogen atom, astraight chain or branched alkoxy group, or a straight chain or branchedalkyl group.

In the aforementioned chemical formula (R¹A2), more preferably, R¹¹-R¹³may be the same or different and each is a hydrogen atom, a straightchain or branched alkoxy group having 1-12 carbon atoms, or a straightchain or branched alkyl group having 1-12 carbon atoms.

In the glycoside compound of the present invention, R¹ in theaforementioned chemical formula (1) is more preferably a hydrogen atom,or a substituent represented by the following chemical formula (R¹Aa),(R¹Ba), (R¹Ca), (R¹Cb) or (R¹Da).

In the aforementioned chemical formulas (R¹R²A) and (R¹R²B) in theglycoside compound of the present invention, respective R^(1a) may bethe same or different, as mentioned above, and each is a hydrogen atom,a straight chain or branched alkyl group, or a straight chain orbranched alkoxy group. The aforementioned straight chain or branchedalkyl group is more preferably a straight chain or branched alkyl grouphaving 1-12 carbon atoms. The aforementioned straight chain or branchedalkoxy group is more preferably a straight chain or branched alkoxygroup having 1-12 carbon atoms.

In the glycoside compound of the present invention, the glycosidecompound represented by the aforementioned chemical formula (1) ispreferably the glycoside compound represented by the aforementionedchemical formula (2).

In the aforementioned chemical formula (2),

B, R¹ and R³ are as defined for the aforementioned chemical formula (1),

provided that R¹ is a protecting group,

R^(2a) and R^(2b) may be the same or different and each is a hydrogenatom or any substituent,

or R^(2a) and R^(2b) optionally form a nonaromatic ring, in conjunctionwith a nitrogen atom to which they are bonded, the aforementionednonaromatic ring optionally has a nitrogen atom, an oxygen atom or asulfur atom, besides the aforementioned nitrogen atom, and optionallyhas a substituent, and

R^(2c) is a hydrogen atom, an electron-withdrawing group or anysubstituent, which may be optionally substituted by anelectron-withdrawing group [D²].

In the aforementioned chemical formula (2), R^(2a) and R^(2b) are each ahydrogen atom, halogen, a hydrocarbon group, a straight chain orbranched alkyl group, a straight chain or branched alkenyl group, astraight chain or branched alkynyl group, a straight chain or branchedhaloalkyl group, an aryl group, a heteroaryl group, a straight chain orbranched arylalkyl group, a cycloalkyl group, a cycloalkenyl group, astraight chain or branched cycloalkylalkyl group, a straight chain orbranched cyclylalkyl group, a straight chain or branched hydroxyalkylgroup, a straight chain or branched alkoxyalkyl group, a straight chainor branched aminoalkyl group, a straight chain or branchedheterocyclylalkenyl group, a straight chain or branchedheterocyclylalkyl group, a straight chain or branched heteroarylalkylgroup, a silyl group, a silyloxyalkyl group, a mono-, di- ortrialkylsilyl group, or a mono-, di- or trialkylsilyloxyalkyl group,which is preferably optionally further substituted or not substituted byan electron-withdrawing group. Alternatively, R^(2a) and R^(2b) mayform, in conjunction with the nitrogen atom bonded thereto, a 5- or6-membered nonaromatic ring, wherein the aforementioned nonaromatic ringmay or may not have a nitrogen atom, an oxygen atom or a sulfur atombesides the aforementioned nitrogen atom, and may or may not furtherhave a substituent.

In the aforementioned chemical formula (2), more preferably, R^(2a) andR^(2b) are each a hydrogen atom, halogen, a straight chain or branchedalkyl group having 1-12 carbon atoms, a straight chain or branchedalkenyl group having 2-12 carbon atoms, a straight chain or branchedalkynyl group having 2-12 carbon atoms, a straight chain or branchedhaloalkyl group having 1-12 carbon atoms, an aryl group having 5-24carbon atoms, a heteroaryl group having 5-24 carbon atoms, a straightchain or branched arylalkyl group having 6-30 carbon atoms, a cycloalkylgroup having 3-24 carbon atoms, a cycloalkenyl group having 3-24 carbonatoms, a straight chain or branched cycloalkylalkyl group having 4-30carbon atoms, a straight chain or branched cyclylalkyl group having 4-30carbon atoms, a straight chain or branched hydroxyalkyl group having1-12 carbon atoms, a straight chain or branched alkoxyalkyl group having2-12 carbon atoms, a straight chain or branched aminoalkyl group having1-12 carbon atoms, a straight chain or branched heterocyclylalkenylgroup having 5-30 carbon atoms, a straight chain or branchedheterocyclylalkyl group having 4-30 carbon atoms, a straight chain orbranched heteroarylalkyl group having 6-30 carbon atoms, a silyl group,a silyloxyalkyl group having 1-12 carbon atoms, a mono-, di- ortrialkylsilyl group having alkyl carbon number 1-12, or an alkyl grouphaving 1-12 carbon atoms and substituted by a mono-, di- ortrialkylsilyloxy group having alkyl carbon number 1-12, which may befurther substituted or not substituted by an electron-withdrawing group.Alternatively, R^(2a) and R^(2b) may form, in conjunction with thenitrogen atom bonded thereto, a 5- or 6-membered nonaromatic ring. Theaforementioned nonaromatic ring may or may not have a nitrogen atom, anoxygen atom or a sulfur atom besides the aforementioned nitrogen atom,and may or may not further have a substituent.

In the aforementioned chemical formula (2), more preferably, R^(2a) andR^(2b) are each a methyl group, an ethyl group, an isopropyl group, or at-butyl group, or R^(2a) and R^(2b) form, in conjunction with a nitrogenatom bonded thereto, a piperidyl group, a morpholino group, a pyrrolidylgroup, a thiomorpholino group, or other nitrogen-containing alicyclicgroup. More specifically, for example, in the aforementioned chemicalformula (2), —NR^(2a)R^(2b) is more preferably a diisopropylamino group,a diethylamino group, an ethylmethylamino group, a pyrrolidyl(particularly, pyrrolidin-1-yl) group, a piperidyl (particularly,piperidin-1-yl) group, a morpholino (particularly, morpholin-1-yl)group, a thiomorpholino (particularly, thiomorpholin-1-yl) group, or anarylamino group.

In the aforementioned chemical formula (2), R^(2c) is a hydrogen atom,halogen, a hydrocarbon group, a straight chain or branched alkyl group,a straight chain or branched alkenyl group, a straight chain or branchedalkynyl group, a straight chain or branched haloalkyl group, an arylgroup, a heteroaryl group, a straight chain or branched arylalkyl group,a cycloalkyl group, a cycloalkenyl group, a straight chain or branchedcycloalkylalkyl group, a straight chain or branched cyclylalkyl group, astraight chain or branched hydroxyalkyl group, a straight chain orbranched alkoxyalkyl group, a straight chain or branched aminoalkylgroup, a straight chain or branched heterocyclylalkenyl group, astraight chain or branched heterocyclylalkyl group, a straight chain orbranched heteroarylalkyl group, a silyl group, a silyloxyalkyl group, amono-, di- or trialkylsilyl group, or a mono-, di- ortrialkylsilyloxyalkyl group, and further preferably may or may not besubstituted by an electron-withdrawing group [D²].

In the aforementioned chemical formula (2), R^(2c) is a hydrogen atom,halogen, a straight chain or branched alkyl group having 1-12 carbonatoms, a straight chain or branched alkenyl group having 2-12 carbonatoms, a straight chain or branched alkynyl group having 2-12 carbonatoms, a straight chain or branched haloalkyl group having 1-12 carbonatoms, an aryl group having 5-24 carbon atoms, a heteroaryl group having5-24 carbon atoms, a straight chain or branched arylalkyl group having6-30 carbon atoms, a cycloalkyl group having 3-24 carbon atoms, acycloalkenyl group having 3-24 carbon atoms, a straight chain orbranched cycloalkylalkyl group having 4-30 carbon atoms, a straightchain or branched cyclylalkyl group having 4-30 carbon atoms, a straightchain or branched hydroxyalkyl group having 1-12 carbon atoms, astraight chain or branched alkoxyalkyl group having 2-12 carbon atoms, astraight chain or branched aminoalkyl group having 1-12 carbon atoms, astraight chain or branched heterocyclylalkenyl group having 6-30 carbonatoms, a straight chain or branched heterocyclylalkyl group having 4-30carbon atoms, a straight chain or branched heteroarylalkyl group having6-30 carbon atoms, a silyl group, a silyloxyalkyl group having 1-12carbon atoms, a mono-, di- or trialkylsilyl group having alkyl carbonnumber 1-12, or an alkyl group having 1-12 carbon atoms and substitutedby a mono-, di- or trialkylsilyloxy group having alkyl carbon number1-12, and more preferably may or may not be further substituted by anelectron-withdrawing group [D²].

In the aforementioned chemical formula (2), R^(2c) is more preferably astraight chain or branched alkyl group substituted by anelectron-withdrawing group [D²]. In the aforementioned chemical formula(2), R^(2c) is more preferably a straight chain or branched alkyl grouphaving 1-12 carbon atoms and substituted by an electron-withdrawinggroup [D²].

In the aforementioned chemical formula (2), the aforementionedelectron-withdrawing group [D²] for R^(2c) is preferably a cyano group,a nitro group, an alkylsulfonyl group, halogen, an arylsulfonyl group, atrihalomethyl group, or a trialkylamino group. The aforementionedtrihalomethyl group is, for example, a trichloromethyl group, atrifluoromethyl group or the like.

In the aforementioned chemical formula (2), R^(2c) is particularlypreferably an alkenyl group or an ethynyl group, or substituted by anelectron-withdrawing group [D²] and form, together with [D²], acyanoethyl group.

In the glycoside compound of the present invention, the glycosidecompound represented by the aforementioned chemical formula (1) is morepreferably a glycoside compound represented by the following chemicalformula (3).

In the aforementioned chemical formula (3),

B and n are as defined for the aforementioned chemical formula (1), and

DMTr is a 4,4′-dimethoxy(triphenylmethyl) group.

In the glycoside compound of the present invention, the nucleic acidbase for B in the aforementioned chemical formula (1) is notparticularly limited, but is preferably an atomic group having a naturalnucleic acid base skeleton. The aforementioned natural nucleic acid basemay or may not have a protecting group. The aforementioned naturalnucleic acid base is more preferably adenine, cytosine, guanine, uracil,thymine, or other nitrogen-containing aromatic ring. In theaforementioned chemical formula (1), B is more preferably bonded to theD-ribose skeleton in the aforementioned chemical formula (1) at the9-position nitrogen of adenine, the 1-position nitrogen of cytosine,9-position nitrogen of guanine, the 1-position nitrogen of uracil or the1-position nitrogen of thymine. In addition, as for the nucleic acidbase for B, the nucleic acid base (e.g., the aforementioned nucleicbases such as adenine, cytosine, guanine, uracil, thymine and the like)may be substituted or not substituted by any substituent. Examples ofthe aforementioned substituent include halogen, an acyl group, an alkylgroup, an arylalkyl group, an alkoxy group, an alkoxyalkyl group, ahydroxy group, an amino group, a monoalkylamino group, a dialkylaminogroup, a carboxy group, a cyano group, a nitro group and the like. Thesesubstituents may be 0, 1 or plural (for example, 2-3). When they are inplurality, the kind thereof may be one or plural.

As mentioned above, B may or may not have a protecting group. Forexample, when the aforementioned nucleic acid base for B has an aminogroup (amino substituent) outside the ring (e.g., the aforementionednucleic acid base is adenine, guanine, cytosine etc.), theaforementioned amino group may be protected by a protecting group. Theaforementioned amino-protecting group is not particularly limited and,for example, may be the same as the protecting group etc. used in knownnucleic acids chemistry. Examples of the aforementioned amino-protectinggroup include acyl group. Examples of the aforementioned acyl groupinclude benzoyl group, 4-methoxybenzoyl group, acetyl group, propionylgroup, butyryl group, isobutyryl group, phenylacetyl group,phenoxyacetyl group, 4-tert-butylphenoxyacetyl group,4-isopropylphenoxyacetyl group and the like. Other than acyl group, forexample, a (dimethylamino)methylene group and the like.

In the glycoside compound of the present invention, the glycosidecompound represented by the aforementioned chemical formula (1) is morepreferably a glycoside compound represented by the following chemicalformula (1A^(Ac)), (1C^(Ac)), (1G^(Pac)) or (1U).

In the aforementioned chemical formulas (1A^(Ac)), (1C^(Ac)), (1G^(Pac))and (1U), n are as defined for the aforementioned chemical formula (1).

In the aforementioned chemical formula (1), n=1 is particularlypreferable from the aspects of easiness of synthesis and the like.

When an isomer such as enantiomer, tautomer or stereoisomer (e.g.,geometric isomer, conformational isomer and optical isomer) and the likeis present in the novel compounds provided by the present invention suchas the glycoside compound, ether and the like of the present invention(hereinafter sometimes to be simply referred to as “the compound of thepresent invention”), all isomers are encompassed in the compound of thepresent invention. For example, while the chemical formulas showing theglycoside compounds of the present invention (the aforementionedchemical formulas (1), (2) and (3) etc.) depicts as if the sugarskeleton of glycoside is D-ribose, it may be an enantiomer thereof,i.e., L-ribose. When the compound of the present invention can form asalt, such salt is also encompassed in the compound of the presentinvention. The aforementioned salt of the compound of the presentinvention may be an acid addition salt or a base addition salt.Furthermore, an acid that forms the aforementioned acid addition saltmay be an inorganic acid or an organic acid, and a base that forms theaforementioned base addition salt may be an inorganic base or an organicbase. While the aforementioned inorganic acid is not particularlylimited, for example, sulfuric acid, phosphoric acid, hydrofluoric acid,hydrochloric acid, hydrobromic acid, hydroiodic acid, hypofluorous acid,hypochlorous acid, hypobromous acid, hypoiodous acid, fluorous acid,chlorous acid, bromous acid, iodous acid, fluorine acid, chlorine acid,bromine acid, iodine acid, perfluoric acid, perchloric acid, perbromicacid, periodic acid and the like can be mentioned. While theaforementioned organic acid is not particularly limited, for example,p-toluenesulfonic acid, methanesulfonic acid, oxalic acid,p-bromobenzenesulfonic acid, carbonic acid, succinic acid, citric acid,benzoic acid, acetic acid and the like can be mentioned. While theaforementioned inorganic base is not particularly limited, for example,ammonium hydroxide, alkali metal hydroxide, alkaline earth metalhydroxide, carbonate and hydrogencarbonates and the like can bementioned and, more specifically, for example, sodium hydroxide,potassium hydroxide, potassium carbonate, sodium carbonate, sodiumhydrogen carbonate, potassium hydrogen carbonate, calcium hydroxide andcalcium carbonate and the like can be mentioned. The aforementionedorganic base is not particularly limited and, for example, ethanolamine,triethylamine and tris(hydroxymethyl)aminomethane and the like can bementioned. The production method of these salts is not particularlylimited, and they can be produced by, for example, a method includingappropriately adding the aforementioned acid or base to theaforementioned electron donor acceptor connected molecule by a knownmethod and the like. When an isomer is present in the substituent andthe like, any isomer can be used. For example, the “naphthyl group” maybe a 1-naphthyl group or a 2-naphthyl group, and the “propyl group” maybe an n-propyl group or an isopropyl group.

In the present invention, “alkyl” includes, for example, linear orbranched alkyl. The carbon number of the aforementioned alkyl is notparticularly limited and, for example, 1-30, preferably 1-12, 1-6 or1-4. Examples of the aforementioned alkyl include methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl,pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl,icosyl and the like. Preferably, for example, methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl,isopentyl, neopentyl, n-hexyl, isohexyl and the like can be mentioned.The same applies to a group containing an alkyl group in the structure(alkylamino group, alkoxy group etc.), and a group induced from an alkylgroup (haloalkyl group, hydroxyalkyl group, aminoalkyl group, alkanoylgroup etc.).

In the present invention, “alkenyl” includes, for example, linear orbranched alkenyl. The aforementioned alkenyl is, for example, theaforementioned alkyl containing one or plural double bonds and the like.The carbon number of the aforementioned alkenyl is not particularlylimited and, for example, the same as for the aforementioned alkyl andpreferably 2-12 or 2-8. Examples of the aforementioned alkenyl includevinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl,1,3-butadienyl, 3-methyl-2-butenyl and the like.

In the present invention, “alkynyl” includes, for example, linear orbranched alkynyl. The aforementioned alkynyl is, for example, theaforementioned alkyl containing one or plural triple bonds and the like.The carbon number of the aforementioned alkynyl is not particularlylimited and, for example, the same as for the aforementioned alkyl andpreferably 2-12 or 2-8. Examples of the aforementioned alkynyl includeethynyl, propynyl, butynyl and the like. The aforementioned alkynyl mayfurther have, for example, one or plural double bonds.

In the present invention, “aryl” includes, for example, a monocyclicaromatic hydrocarbon group and a polycyclic aromatic hydrocarbon group.Examples of the aforementioned monocyclic aromatic hydrocarbon groupinclude phenyl and the like. Examples of the aforementioned polycyclicaromatic hydrocarbon group include 1-naphthyl, 2-naphthyl, 1-anthryl,2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl,4-phenanthryl, 9-phenanthryl and the like. Preferably, for example,phenyl, naphthyl such as 1-naphthyl and 2-naphthyl and the like, and thelike can be mentioned.

In the present invention, “heteroaryl” includes, for example, amonocyclic aromatic heterocyclic group and a fused aromatic heterocyclicgroup. Examples of the aforementioned heteroaryl include furyl (e.g.,2-furyl, 3-furyl), thienyl (e.g., 2-thienyl, 3-thienyl), pyrrolyl (e.g.,1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl), imidazolyl (e.g., 1-imidazolyl,2-imidazolyl, 4-imidazolyl), pyrazolyl (e.g., 1-pyrazolyl, 3-pyrazolyl,4-pyrazolyl), triazolyl (e.g., 1,2,4-triazol-1-yl, 1,2,4-triazol-3-yl,1,2,4-triazol-4-yl), tetrazolyl (e.g., 1-tetrazolyl, 2-tetrazolyl,5-tetrazolyl), oxazolyl (e.g., 2-oxazolyl, 4-oxazolyl, 5-oxazolyl),isoxazolyl (e.g., 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl), thiazolyl(e.g., 2-thiazolyl, 4-thiazolyl, 5-thiazolyl), thiadiazolyl,isothiazolyl (e.g., 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl),pyridyl (e.g., 2-pyridyl, 3-pyridyl, 4-pyridyl), pyridazinyl (e.g.,3-pyridazinyl, 4-pyridazinyl), pyrimidinyl (e.g., 2-pyrimidinyl,4-pyrimidinyl, 5-pyrimidinyl), furazanyl (e.g., 3-furazanyl), pyrazinyl(e.g., 2-pyrazinyl), oxadiazolyl (e.g., 1,3,4-oxadiazol-2-yl),benzofuryl (e.g., 2-benzo[b]furyl, -benzo[b]furyl, 4-benzo[b]furyl,5-benzo[b]furyl, 6-benzo[b]furyl, 7-benzo[b]furyl), benzothienyl (e.g.,2-benzo[b]thienyl, 3-benzo[b]thienyl, 4-benzo[b]thienyl,5-benzo[b]thienyl, 6-benzo[b]thienyl, 7-benzo[b]thienyl), benzimidazolyl(e.g., 1-benzimidazolyl, 2-benzimidazolyl, 4-benzimidazolyl,5-benzimidazolyl), dibenzofuryl, benzoxazolyl, benzothiazolyl,quinoxalyl (e.g., 2-quinoxalinyl, 5-quinoxalinyl, 6-quinoxalinyl),cinnolinyl (e.g., 3-cinnolinyl, 4-cinnolinyl, 5-cinnolinyl,6-cinnolinyl, 7-cinnolinyl, 8-cinnolinyl), quinazolyl (e.g.,2-quinazolinyl, 4-quinazolinyl, 5-quinazolinyl, 6-quinazolinyl,7-quinazolinyl, 8-quinazolinyl), quinolyl (e.g., 2-quinolyl, 3-quinolyl,4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl, 8-quinolyl),phthalazinyl (e.g., 1-phthalazinyl, 5-phthalazinyl, 6-phthalazinyl),isoquinolyl (e.g., 1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl,5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl, 8-isoquinolyl), puryl,pteridinyl (e.g., 2-pteridinyl, 4-pteridinyl, 6-pteridinyl,7-pteridinyl), carbazolyl, phenanthridinyl, acridinyl (e.g.,1-acridinyl, 2-acridinyl, 3-acridinyl, 4-acridinyl, 9-acridinyl),indolyl (e.g., 1-indolyl, 2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl,6-indolyl, 7-indolyl), isoindolyl, phenazinyl (e.g., 1-phenazinyl,2-phenazinyl) or phenothiazinyl (e.g., 1-phenothiazinyl,2-phenothiazinyl, 3-phenothiazinyl, 4-phenothiazinyl) and the like.

In the present invention, “cycloalkyl” is, for example, a cyclicsaturated hydrocarbon group, and the carbon number is not particularlylimited and is, for example, 3-24 or 3-15. Examples of theaforementioned cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, bridged cyclic hydrocarbon group,spirohydrocarbon group and the like, preferably, cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, bridged cyclic hydrocarbon groupand the like.

In the present invention, the “bridged cyclic hydrocarbon group” is, forexample, bicyclo[2.1.0]pentyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyland bicyclo[3.2.1]octyl, tricyclo[2.2.1.0]heptyl, bicyclo[3.3.1]nonane,1-adamantyl, 2-adamantyl or the like.

In the present invention, the “spirohydrocarbon group” is, for example,spiro[3.4]octyl or the like.

In the present invention, “cycloalkenyl” includes, for example, a cyclicunsaturated aliphatic hydrocarbon group, and the carbon number is, forexample, 3-24 or 3-7. Examples of the aforementioned group includecyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyland the like, preferably, cyclopropenyl, cyclobutenyl, cyclopentenyl,cyclohexenyl and the like. The aforementioned cycloalkenyl includes, forexample, a bridged cyclic hydrocarbon group and a spirohydrocarbon grouphaving an unsaturated bond in the ring.

In the present invention, “arylalkyl” is, for example, benzyl,2-phenethyl, naphthalenylmethyl or the like, “cycloalkylalkyl” or“cyclylalkyl” is, for example, cyclohexylmethyl, adamantylmethyl or thelike, and “hydroxyalkyl” is, for example, hydroxymethyl and2-hydroxyethyl or the like.

In the present invention, “alkoxy” includes, for example, theaforementioned alkyl-O— group and, for example, methoxy, ethoxy,n-propoxy, isopropoxy, n-butoxy and the like can be mentioned, and“alkoxyalkyl” is, for example, methoxymethyl or the like, and“aminoalkyl” is, for example, 2-aminoethyl or the like.

In the present invention, “cyclyl” is any cyclic atomic group, and ispreferably a nonaromatic saturated or unsaturated cyclic substituent.The carbon number thereof is not particularly limited and is, forexample, 3-24.

In the present invention, “heterocyclyl” is, for example, 1-pyrrolinyl,2-pyrrolinyl, 3-pyrrolinyl, 1-pyrrolidinyl, 2-pyrrolidinyl,3-pyrrolidinyl, pyrrolidinone, 1-imidazolinyl, 2-imidazolinyl,4-imidazolinyl, 1-imidazolidinyl, 2-imidazolidinyl, 4-imidazolidinyl,imidazolidinone, 1-pyrazolinyl, 3-pyrazolinyl, 4-pyrazolinyl,1-pyrazolidinyl, 3-pyrazolidinyl, 4-pyrazolidinyl, piperidinone,piperidino, 2-piperidinyl, 3-piperidinyl, 4-piperidinyl, 1-piperazinyl,2-piperazinyl, piperazinone, 2-morpholinyl, 3-morpholinyl, morpholino,tetrahydropyranyl, tetrahydrofuranyl or the like.

In the present invention, “heterocyclylalkyl” includes, for example,piperidinylmethyl, piperazinylmethyl and the like, “heterocyclylalkenyl”includes, for example, 2-piperidinylethenyl and the like, and“heteroarylalkyl” includes, for example, pyridylmethyl,quinolin-3-ylmethyl and the like.

In the present invention, “silyl” includes, a group represented by theformula R₃Si—, wherein R is, independently, selected from theaforementioned alkyl, aryl and cycloalkyl and, for example, atrimethylsilyl group, a tert-butyldimethylsilyl group and the like canbe mentioned. The “silyloxy” is, for example, a trimethylsilyloxy groupand the like, and “silyloxyalkyl”, for example, trimethylsilyloxymethylor the like.

In the present invention, “alkylene” is, for example, methylene,ethylene, propylene or the like.

In the present invention, “acyl” is not particularly limited and, forexample, formyl, acetyl, propionyl, isobutyryl, valeryl, isovaleryl,pivaloyl, hexanoyl, cyclohexanoyl, benzoyl, ethoxycarbonyl, and the likecan be mentioned. The same applies to a group containing an acyl groupin the structure (acyloxy group, alkanoyloxy group etc.). In the presentinvention, moreover, the carbon number of the acyl group containscarbonyl carbon and, for example, an alkanoyl group (acyl group) havinga carbon number 1 means a formyl group.

In the present invention, “halogen” refers to any halogen element, whichis, for example, fluorine, chlorine, bromine or iodine.

In the present invention, “perfluoroalkyl” is not particularly limitedand, for example, a perfluoroalkyl group induced from a straight chainor branched alkyl group having 1-30 carbon atoms can be mentioned. Theaforementioned “perfluoroalkyl” is more specifically, for example, aperfluoroalkyl group induced from a group such as methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl,pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl nonadecyl,icosyl and the like. The same applies to a group containing aperfluoroalkyl group in the structure (perfluoroalkylsulfonyl group,perfluoroacyl group etc.).

In the present invention, the aforementioned various to groups areoptionally substituted. Examples of the aforementioned substituentinclude hydroxy, carboxy, halogen, alkyl halide (e.g., CF₃, CH₂CF₃,CH₂CCl₃), nitro, nitroso, cyano, alkyl (e.g., methyl, ethyl, isopropyl,tert-butyl), alkenyl (e.g., vinyl), alkynyl (e.g., ethynyl), cycloalkyl(e.g., cyclopropyl, adamantyl), cycloalkylalkyl (e.g., cyclohexylmethyl,adamantylmethyl), cycloalkenyl (e.g., cyclopropenyl), aryl (e.g.,phenyl, naphthyl), arylalkyl (e.g., benzyl, phenethyl), heteroaryl(e.g., pyridyl, furyl), heteroarylalkyl (e.g., pyridylmethyl),heterocyclyl (e.g., piperidyl), heterocyclylalkyl (e.g.,morpholylmethyl), alkoxy (e.g., methoxy, ethoxy, propoxy, butoxy),halogenated alkoxy (e.g., OCF₃), alkenyloxy (e.g., vinyloxy, allyloxy),aryloxy (e.g., phenyloxy), alkyloxycarbonyl (e.g., methoxycarbonyl,ethoxycarbonyl, tert-butoxycarbonyl), arylalkyloxy (e.g., benzyloxy),amino[alkylamino (e.g., methylamino, ethylamino, dimethylamino),acylamino (e.g., acetylamino, benzoylamino), arylalkylamino (e.g.,benzylamino, tritylamino), hydroxyamino], alkylaminoalkyl (e.g.,diethylaminomethyl), sulfamoyl, oxo and the like.

In the present invention, when the aforementioned various groups arehetero rings or contain a hetero ring, the “carbon number” also includesthe number of hetero atoms constituting the aforementioned hetero ring.

2. Production Method of Thioether

The first production method of thioether in the present invention is, asmentioned above, a method of producing thioether represented by thefollowing chemical formula (103) by a coupling reaction of thiol orthioalkoxide represented by the following chemical formulas (101a) and(101b) with a halide represented by the following chemical formula(102).

In the aforementioned chemical formulas (101a), (101b) and (103),

R⁴ and R⁵ are each a hydrocarbon group, a straight chain or branchedalkyl group, a straight chain or branched alkenyl group, a straightchain or branched alkynyl group, an aryl group, a straight chain orbranched arylalkyl group, a cycloalkyl group, a cycloalkenyl group, astraight chain or branched cycloalkylalkyl group, a straight chain orbranched cyclylalkyl group, or a straight chain or branched alkoxyalkylgroup, which may be the same or different,

in the aforementioned chemical formulas (101a) and (101b),

M¹ and M² may be the same or different and each is a hydrogen atom or ametal,

in the aforementioned chemical formulas (102) and (103),

n is a positive integer, and

in the aforementioned chemical formula (102),

X¹ and X² may be the same or different and each is halogen.

The thioether compound represented by the aforementioned chemicalformula (103) can be used as, for example, an intermediate useful forthe synthesis of pharmaceutical products. In conventional synthesismethods, the thioether compound (103) could be obtained only in a lowyield. However, the present inventors have found a method capable ofsynthesizing the same in a high yield, and invented the first and thesecond production methods of the thioether in the present invention. Theproduction method of thioether of the present invention can obtain, forexample, the thioether compound (103) in a high yield of not less than70% relative to the halide (102), as shown in the below-mentionedExample 1.

In the aforementioned chemical formulas (101a), (101b) and (103), R⁴ andR⁵ are each a straight chain or branched alkyl group having 1-12 carbonatoms, a straight chain or branched alkenyl group having 2-12 carbonatoms, a straight chain or branched alkynyl group having 2-12 carbonatoms, an aryl group having 5-24 carbon atoms, a straight chain orbranched arylalkyl group having 6-30 carbon atoms, a cycloalkyl grouphaving 3-24 carbon atoms, a cycloalkenyl group having 3-24 carbon atoms,a straight chain or branched cycloalkylalkyl group having 4-30 carbonatoms, a straight chain or branched cyclylalkyl group having 4-30 carbonatoms, or a straight chain or branched alkoxyalkyl group having 2-30carbon atoms, and may be preferably the same or different. In addition,in the aforementioned chemical formulas (101a), (101b) and (103), R⁴ andR⁵ are particularly preferably methyl groups.

While both M¹ and M² are not particularly limited, for example, hydrogenatom, alkali metal, alkaline earth metal, transition metal and the likecan be mentioned, and preferred are hydrogen atom, sodium, potassium,calcium, magnesium, aluminum, zinc, iron, copper, yttrium and bismuth.When M¹ and M² are metals, the valence thereof can be any. In addition,while the atomic number of M¹ and M² is indicated as 1:1 to themolecular number of thiol in the aforementioned chemical formulas (101a)and (101b), it is not limited thereto. For example, when M¹ or M² is anx-valent (x is a positive integer) metal ion, the atomic number of M¹ orM² may be 1/x relative to the molecular number of thiol in theaforementioned chemical formula (101a) or (101b). While thethioalkoxides represented by (101a) and (101b) may be different fromeach other, they are preferably the same, since it is convenient andpreferable for the synthesis of (103).

In the aforementioned chemical formula (102), n is not particularlylimited; it is, for example, 1-30, preferably 1-20.

The conditions of the coupling reaction of the thioalkoxides representedby the aforementioned chemical formulas (101a) and (101b), and thehalide represented by the aforementioned chemical formula (102) are notparticularly limited. While the reaction solvent for the aforementionedcoupling reaction is not particularly limited, for example, ketones suchas acetone, methyl ethyl ketone and the like, ethers such as diethylether, THF (tetrahydrofuran), dioxane and the like, nitriles such asacetonitrile etc., and the like can be mentioned. While the reactiontime of the aforementioned coupling reaction is not particularlylimited, it is, for example, 30 min-4 hr, preferably 30 min-2 hr, morepreferably 30 min-1 hr. While the reaction temperature of theaforementioned coupling reaction is not particularly limited, it is, forexample, 15-40° C., preferably, 15-37° C., more preferably 20-37° C.Also, the concentration of the thioalkoxides represented by theaforementioned chemical formulas (101a) and (101b), and the haliderepresented by the aforementioned chemical formula (102) is notparticularly limited, and can be appropriately determined. The substanceamount ratio of the thioalkoxides represented by the aforementionedchemical formulas (101a) and (101b), and the halide represented by theaforementioned chemical formula (102) is not particularly limited andmay be, for example, a stoichiometric mixture ratio or any other ratio.The number of moles of the thioalkoxides represented by theaforementioned chemical formulas (101a) and (101b) is, for example, 1-to 10-fold, preferably 2- to 7-fold, more preferably 3- to 5-fold, ofthe number of moles of the halide represented by the aforementionedchemical formula (102). The reaction conditions of the aforementionedcoupling reaction may be appropriately determined by, for example,referring to the conditions of a known coupling reaction of thioalkoxideand halide and the like, or by reference to the below-mentionedExample 1. Examples of the reference document for known reactionsinclude the reference documents described in the below-mentioned Example1 and the like.

Examples of the aforementioned coupling reaction include the reactionsof the following Scheme 1-2. The reaction of the upper panel of thefollowing Scheme 1-2 is the same as the reaction of the below-mentionedExample 1.

The production method of the halide represented by the aforementionedchemical formula (102) is not particularly limited, either. For example,when a commercially available product of the aforementioned halide, andthe like can be obtained, it may be used directly. For example, thecompound (102-2) in the aforementioned Scheme 1-2 is commerciallyavailable from Aurora Fine Chemicals LLC (US). The aforementionedcompound (102-2) can also be synthesized according to, for example, themethod of Head, Frank S. H., Journal of the Chemical Society, February,1012-15, 1965. In addition, the halide represented by the aforementionedchemical formula (102) may also be produced by, for example, hydrolyzingpara-formaldehyde with hydrohalic acid and the like. While the reactionsolvent for the aforementioned hydrolysis is not particularly limited,for example, water is preferable. For example, halogenated sulfonic acidand the like may be further added to a thick aqueous solution of theaforementioned hydrohalic acid, and the aforementioned hydrolysis may beperformed in the system. While the reaction time of the aforementionedhydrolysis is not particularly limited, it is, for example, 1-24 hr,preferably 1-12 hr, more preferably 2-6 hr. While the reactiontemperature of the aforementioned hydrolysis is not particularlylimited, it is, for example, −20 to 35° C., preferably −10 to 30° C.,more preferably −5 to 25° C. The concentration, substance amount ratioand the like of respective reaction substances are not particularlylimited likewise, and can be appropriately determined. The reactionconditions of the aforementioned hydrolysis may be appropriatelydetermined by, for example, referring to the conditions of knownhydrolysis of para-formaldehyde and the like, or by reference to thebelow-mentioned Example 1. For example, the compound (102-1) in theaforementioned Scheme 1-2 is the same compound as the compound (1002) inthe below-mentioned Example 1, and can be produced according toExample 1. Examples of the reference documents of known reactionsinclude the reference documents described in the below-mentioned Example1 and the like.

Then, the second production method of the thioether in the presentinvention is, as mentioned above, a method of producing thioetherrepresented by the following chemical formula (103) by a couplingreaction of the thioether represented by the following chemical formula(103b) and the alcohol represented by the following chemical formula(104) in the presence of a halogenating agent and a Lewis acid.

In the aforementioned chemical formulas (103b), (104) and (103),

R⁴, R⁵ and R⁶ are each a hydrocarbon group, a straight chain or branchedalkyl group, a straight chain or branched alkenyl group, a straightchain or branched alkynyl group, an aryl group, a straight chain orbranched arylalkyl group, a cycloalkyl group, a cycloalkenyl group, astraight chain or branched cycloalkylalkyl group, a straight chain orbranched cyclylalkyl group, or a straight chain or branched alkoxyalkylgroup, which may be the same or different, and

in the aforementioned chemical formulas (103b) and (103),

n is an integer of two or more.

In the aforementioned chemical formulas (103b), (104) and (103), R⁴, R⁵and R⁶ are each a straight chain or branched alkyl group having 1-12carbon atoms, a straight chain or branched alkenyl group having 2-12carbon atoms, a straight chain or branched alkynyl group having 2-12carbon atoms, an aryl group having 5-24 carbon atoms, a straight chainor branched arylalkyl group having 6-30 carbon atoms, a cycloalkyl grouphaving 3-24 carbon atoms, a cycloalkenyl group having 3-24 carbon atoms,a straight chain or branched cycloalkylalkyl group having 4-30 carbonatoms, a straight chain or branched cyclylalkyl group having 4-30 carbonatoms, or a straight chain or branched alkoxyalkyl group having 6-30carbon atoms, and may be preferably the same or different. In theaforementioned chemical formulas (103b), (104) and (103), R⁴, R⁵ and R⁶are particularly preferably methyl groups.

In the second production method of the thioether in the presentinvention, the aforementioned halogenating agent is not particularlylimited, but preferably at least one selected from the group consistingof N-chlorosuccinimide, N-bromosuccinimide, N-iodosuccinimide, iodine,bromine and chlorine. Also, the aforementioned Lewis acid is notparticularly limited, but preferably at least one selected from thegroup consisting of perfluoroalkylcarboxylic acid,perfluoroalkylsulfonic acid, alkylsulfonic acid and a salt thereof. Theaforementioned Lewis acid is particularly preferably a silver salt oftrifluoromethanesulfonic acid. In addition, in the second productionmethod of the thioether in the present invention, the aforementionedcoupling reaction is preferably performed in the co-presence ofmolecular sieve.

In the second production method of the thioether in the presentinvention, the conditions of the coupling reaction of the thioetherrepresented by the aforementioned chemical formula (103b) and thealcohol represented by the aforementioned chemical formula (104) are notparticularly limited. While the reaction solvent for the aforementionedcoupling reaction is not particularly limited, for example, ketones suchas acetone, methyl ethyl ketone, acetophenone and the like, ethers suchas diethyl ether, THF (tetrahydrofuran), dioxane and the like, nitrilessuch as acetonitrile etc., and the like can be mentioned. While thereaction time of the aforementioned coupling reaction is notparticularly limited, it is, for example, 1-12 hr, preferably 1-8 hr,more preferably 1-4 hr. While the reaction temperature of theaforementioned coupling reaction is not particularly limited, it is, forexample, −75 to 0° C., preferably −60 to −10° C., more preferably −50 to−40° C. The concentrations of the thioether represented by theaforementioned chemical formula (103b) and the alcohol represented bythe aforementioned chemical formula (104) are not particularly limited,and can be appropriately determined. The substance amount ratio of thethioether represented by the aforementioned chemical formula (103b) andthe alcohol represented by the aforementioned chemical formula (104) isnot particularly limited and may be, for example, a stoichiometricmixture ratio or any other ratio. The amount of other reaction substanceto be used is not particularly limited. The number of moles of thethioether represented by the aforementioned chemical formula (103b) is,for example, 0.5- to 2-fold, preferably 0.5- to 1-fold, more preferably0.5-fold, relative to that of the alcohol represented by theaforementioned chemical formula (104). The number of moles of theaforementioned halogenating agent is, for example, 1- to 2-fold,preferably 1- to 1.5-fold, more preferably 1.2-fold, relative to that ofthe alcohol represented by the aforementioned chemical formula (104).The number of moles of the aforementioned Lewis acid is, for example,0.005- to 0.05-fold, preferably 0.01- to 0.025-fold, more preferably0.015-fold, relative to that of the alcohol represented by theaforementioned chemical formula (104). While the amount of the molecularsieve to be used is not particularly limited, it is preferably used inexcess against the aforementioned each reaction substance. The reactionconditions of the aforementioned coupling reaction may be appropriatelydetermined by referring to, for example, the conditions of a knowncoupling reaction of thioether and alcohol, and the like. Examples ofthe reference document of the known coupling reaction of thioether andalcohol include Eur. Pat. Appl. (1995), EP 639577 A1.

In the second production method of the thioether in the presentinvention, examples of the aforementioned coupling reaction of thioetherand alcohol include the reaction shown in the following Scheme 2-2. Inthis way, the chain length of thioether can be extended sequentially. Inthe following Scheme 2-2, “NIS” is N-iodosuccinimide, “TfOAg” is asilver salt of trifluoromethanesulfonic acid, and “MS” is molecularsieve. The compound (105-1) may be synthesized by referring to, forexample, Synthetic Communications, 16(13), 1607-10; 1986 and the like,or a commercially available product may be obtained.

3. Ether

The ether of the present invention is, as mentioned above, an etherrepresented by the following chemical formula (106), an enantiomerthereof, a tautomer or stereoisomer thereof, or a salt thereof.

In the aforementioned chemical formula (106),

R⁴ is a hydrocarbon group, a straight chain or branched alkyl group, astraight chain or branched alkenyl group, a straight chain or branchedalkynyl group, an aryl group, a straight chain or branched arylalkylgroup, a cycloalkyl group, a cycloalkenyl group, a straight chain orbranched cycloalkylalkyl group, a straight chain or branched cyclylalkylgroup, or a straight chain or branched alkoxyalkyl group,

n is a positive integer,

L¹ is an ethylene group (—CH₂CH₂—), wherein hydrogen atoms besides ahydrogen atom bonded to the α-position relative to [D¹] are optionallysubstituted by a straight chain or branched alkyl group, and

[D¹] is an electron-withdrawing group.

In the aforementioned chemical formula (106), R⁴ is preferably astraight chain or branched alkyl group having 1-12 carbon atoms, astraight chain or branched alkenyl group having 2-12 carbon atoms, astraight chain or branched alkynyl group having 2-12 carbon atoms, anaryl group having 5-24 carbon atoms, a straight chain or branchedarylalkyl group having 6-30 carbon atoms, a cycloalkyl group having 3-24carbon atoms, a cycloalkenyl group having 3-24 carbon atoms, a straightchain or branched cycloalkylalkyl group having 4-30 carbon atoms, astraight chain or branched cyclylalkyl group having 4-30 carbon atoms,or a straight chain or branched alkoxyalkyl group having 2-30 carbonatoms. In the aforementioned chemical formula (106), R⁴ is particularlypreferably a methyl group.

In the aforementioned chemical formula (106), the aforementionedstraight chain or branched alkyl group for L¹ may be, for example, astraight chain or branched alkyl group having 1-12 carbon atoms. L¹ isparticularly preferably an unsubstituted ethylene group (—CH₂CH₂—). Inthe aforementioned chemical formula (106), [D¹] is preferably a cyanogroup, a nitro group, an alkylsulfonyl group, halogen, a nitro group, anarylsulfonyl group, a trihalomethyl group, or a trialkylamino group.Examples of the aforementioned trihalomethyl group include atrichloromethyl group, a trifluoromethyl group and the like. In theaforementioned chemical formula (106), n is not particularly limitedand, for example, within the range of 1-30, preferably 1-20.

The ether represented by the aforementioned chemical formula (106) ofthe present invention is preferable as a synthesis intermediate for theaforementioned glycoside compound of the present invention. However, theether of the present invention is not limited thereto and may be usedfor any use.

4. Production Method of Ether

While the production method of the ether represented by theaforementioned chemical formula (106) of the present invention is notparticularly limited, the aforementioned production method of the etherof the present invention is preferable. The production method of theether of the present invention is, as mentioned above, a method ofproducing the ether represented by the aforementioned chemical formula(106) of the present invention by a coupling reaction of the thioetherrepresented by the following chemical formula (103) and the alcoholrepresented by the following chemical formula (105) in the presence of ahalogenating agent and a Lewis acid.

In the aforementioned chemical formulas (103) and (105),

R⁴ is as defined for the aforementioned chemical formula (106),

R⁵ is a hydrocarbon group, a straight chain or branched alkyl group, astraight chain or branched alkenyl group, a straight chain or branchedalkynyl group, an aryl group, a straight chain or branched arylalkylgroup, a cycloalkyl group, a cycloalkenyl group, a straight chain orbranched cycloalkylalkyl group, a straight chain or branched cyclylalkylgroup, or a straight chain or branched alkoxyalkyl group, which may bethe same as or different from R⁴,

in the aforementioned chemical formula (103),

n is as defined for the aforementioned chemical formula (106), and

in the aforementioned chemical formula (105),

L¹ and [D¹] are as defined for the aforementioned chemical formula(106).

In the aforementioned chemical formula (103), R⁵ is a straight chain orbranched alkyl group having 1-12 carbon atoms, a straight chain orbranched alkenyl group having 2-12 carbon atoms, a straight chain orbranched alkynyl group having 2-12 carbon atoms, an aryl group having5-24 carbon atoms, a straight chain or branched arylalkyl group having6-30 carbon atoms, a cycloalkyl group having 3-24 carbon atoms, acycloalkenyl group having 3-24 carbon atoms, a straight chain orbranched cycloalkylalkyl group having 4-30 carbon atoms, a straightchain or branched cyclylalkyl group having 4-30 carbon atoms, or astraight chain or branched alkoxyalkyl group having 2-30 carbon atoms,and may be preferably the same or different. In the aforementionedchemical formula (103), R⁵ is particularly preferably a methyl group.

In the production method of the ether of the present invention, theaforementioned halogenating agent is not particularly limited, and ispreferably at least one selected from the group consisting ofN-chlorosuccinimide, N-bromosuccinimide, N-iodosuccinimide, iodine,bromine and chlorine. Also, the aforementioned Lewis acid is notparticularly limited, but it is preferably at least one selected fromthe group consisting of perfluoroalkylcarboxylic acid,perfluoroalkylsulfonic acid, alkylsulfonic acid and a salt thereof. Theaforementioned Lewis acid is particularly preferably a silver salt oftrifluoromethanesulfonic acid. In addition, in the second productionmethod of the thioether in the present invention, the aforementionedcoupling reaction is preferably performed in the co-presence ofmolecular sieve.

In the production method of the ether of the present invention, theconditions of the coupling reaction of the thioether represented by theaforementioned chemical formula (103) and the alcohol represented by theaforementioned chemical formula (105) are not particularly limited.While the reaction solvent for the aforementioned coupling reaction isnot particularly limited, for example, ketones such as acetone, methylethyl ketone, acetophenone and the like, ethers such as diethyl ether,THF (tetrahydrofuran), dioxane and the like, nitriles such asacetonitrile etc., and the like can be mentioned. While the reactiontime of the aforementioned coupling reaction is not particularlylimited, it is, for example, 1-12 hr, preferably 1-8 hr, more preferably1-4 hr. While the reaction temperature of the aforementioned couplingreaction is not particularly limited, it is, for example, −75 to 0° C.,preferably −60 to −10° C., more preferably −50 to −40° C. Theconcentration of the thioether represented by the aforementionedchemical formula (103) and the alcohol represented by the aforementionedchemical formula (105) is not particularly limited, and can beappropriately determined. The substance amount ratio of the thioetherrepresented by the aforementioned chemical formula (103) and the alcoholrepresented by the aforementioned chemical formula (105) is notparticularly limited and may be, for example, a stoichiometric mixtureratio or any other ratio. Also, the amount of other reaction substanceto be used is not particularly limited. The number of moles of thethioether represented by the aforementioned chemical formula (103) is,for example, 0.5- to 2-fold, preferably 0.5- to 1-fold, more preferably0.5-fold, relative to that of the alcohol represented by theaforementioned chemical formula (105). The number of moles of theaforementioned halogenating agent is, for example, 1- to 2-fold,preferably 1- to 1.5-fold, more preferably 1.2-fold, relative to that ofthe alcohol represented by the aforementioned chemical formula (105).The number of moles of the aforementioned Lewis acid is, for example,0.005- to 0.05-fold, preferably 0.01- to 0.025-fold, more preferably0.015-fold, relative to that of the alcohol represented by theaforementioned chemical formula (105). While the amount of the molecularsieve to be used is not particularly limited, it is preferably used inexcess against the aforementioned each reaction substance. The reactionconditions of the aforementioned coupling reaction may be appropriatelydetermined by referring to, for example, the conditions of a knowncoupling reaction of thioether and alcohol, and the like, or byreference to the below-mentioned Example 1. Examples of the referencedocument for the known coupling reaction of thioether and alcoholinclude Eur. Pat. Appl. (1995), EP 639577 A1.

In the production method of the ether of the present invention, theproduction method of the thioether represented by the aforementionedchemical formula (103) is not particularly limited, and it is preferablythe aforementioned first or second production method of the thioether inthe present invention. That is, the production method of the etherrepresented by the aforementioned chemical formula (106) of the presentinvention preferably further includes a step of producing the thioetherrepresented by the aforementioned chemical formula (103) according tothe aforementioned first or second production method of the thioether inthe present invention.

5. Production Method of Glycoside Compound

The production method of the glycoside compound of the present inventionis not particularly limited and can be appropriately performed byreferring to, for example, a known production method of glycoside (ACEamidite etc.). For example, the production method described in CurrentProtocols in Nucleic Acid Chemistry, unit 2.16.1-2.16.31 (2009). may bereferred to.

The glycoside of the present invention is preferably produced by, forexample, the aforementioned production method of the present invention(production method of glycoside compound). The aforementioned productionmethod of the present invention (production method of the glycosidecompound) includes, as mentioned above, a coupling step including acoupling reaction of a glycoside compound represented by the followingchemical formula (107) and an ether represented by the followingchemical formula (106), in the presence of a halogenating agent and aLewis acid to give a glycoside compound represented by the followingchemical formula (1a). The glycoside compound represented by thefollowing chemical formula (1a) is a glycoside compound wherein R¹ andR² in the aforementioned chemical formula (1) in conjunction form anatomic group represented by the aforementioned chemical formula (R¹R²A)or (R¹R²B).

In the aforementioned chemical formulas (107) and (1a),

L² is an atomic group represented by the aforementioned chemical formula(R¹R²A) or (R¹R²B),

B is as defined for the aforementioned chemical formula (1),

in the aforementioned chemical formula (106),

R⁴ is a hydrocarbon group, a straight chain or branched alkyl group, astraight chain or branched alkenyl group, a straight chain or branchedalkynyl group, an aryl group, a straight chain or branched arylalkylgroup, a cycloalkyl group, a cycloalkenyl group, a straight chain orbranched cycloalkylalkyl group, a straight chain or branched cyclylalkylgroup, or a straight chain or branched alkoxyalkyl group, and

in the aforementioned chemical formula (106) and (1a),

L¹, n and [D¹] are as defined for the aforementioned chemical formula(1).

The method of obtaining the glycoside represented by the aforementionedchemical formula (107) is not particularly limited and, for example, itmay be obtained as a commercially available product or may be producedby a known method. In the aforementioned coupling reaction (theaforementioned Scheme 4), the aforementioned halogenating agent is notparticularly limited, but preferably at least one selected from thegroup consisting of N-chlorosuccinimide, N-bromosuccinimide,N-iodosuccinimide, iodine, bromine and chlorine. Also, theaforementioned Lewis acid is not particularly limited, but preferably atleast one selected from the group consisting of perfluoroalkylcarboxylicacid, perfluoroalkylsulfonic acid, alkylsulfonic acid and a saltthereof. The aforementioned Lewis acid is particularly preferablytrifluoromethanesulfonic acid or a salt thereof.

In the production method of the glycoside compound of the presentinvention, the conditions of the coupling reaction of the thioetherrepresented by the aforementioned chemical formula (107) and the etherrepresented by the aforementioned chemical formula (106) are notparticularly limited. While the reaction solvent for the aforementionedcoupling reaction is not particularly limited, for example, ketones suchas acetone, methyl ethyl ketone, acetophenone and the like, ethers suchas diethyl ether, THF (tetrahydrofuran), dioxane and the like, nitrilessuch as acetonitrile etc., and the like can be mentioned. While thereaction time of the aforementioned coupling reaction is notparticularly limited, it is, for example, 1-12 hr, preferably 1-8 hr,more preferably 1-4 hr. While the reaction temperature of theaforementioned coupling reaction is not particularly limited, it is, forexample, −75 to 0° C., preferably −60 to −10° C., more preferably −50 to−40° C. The concentration of the glycoside compound represented by theaforementioned chemical formula (107) and the ether represented by theaforementioned chemical formula (106) is not particularly limited, andcan be appropriately determined. The substance amount ratio of theglycoside compound represented by the aforementioned chemical formula(107) and the ether represented by the aforementioned chemical formula(106) is not particularly limited and may be, for example, astoichiometric mixture ratio or any other ratio. Also, the amount ofother reaction substance to be used is not particularly limited. Thenumber of moles of the glycoside compound represented by theaforementioned chemical formula (107) is, for example, 1- to 5-fold,preferably 1- to 3-fold, more preferably 1- to 1.5-fold, relative tothat of the ether represented by the aforementioned chemical formula(106). The number of moles of the aforementioned halogenating agent is,for example, 1- to 3-fold, preferably 1- to 2-fold, more preferably 1-to 1.5-fold, relative to that of the ether represented by theaforementioned chemical formula (106). The number of moles of theaforementioned Lewis acid is, for example, 0.005- to 0.05-fold,preferably 0.01- to 0.025-fold, more preferably 0.015-fold, relative tothat of the ether represented by the aforementioned chemical formula(106). The reaction conditions of the aforementioned coupling reactionmay be appropriately determined by referring to, for example, asmentioned above, the conditions of a known amidite synthesis of theglycoside compound, and the like, or by reference to any of thebelow-mentioned Examples 2 to 5.

The production method of the glycoside compound of the present inventionpreferably further includes a deprotection step for removing theaforementioned atomic group L² from the glycoside compound representedby the aforementioned chemical formula (1a) to produce glycosidecompound represented by the following chemical formula (1b). In thiscase, the glycoside compound represented by the following chemicalformula (1b) is a glycoside compound of the aforementioned chemicalformula (1) wherein R¹ and R² are hydrogen atoms.

In the aforementioned chemical formula (1b),

B, L¹, n and [D¹] are as defined for the aforementioned chemical formula(1).

In the aforementioned deprotection step, while the conditions of thedeprotection are not particularly limited, for example, a knowndeprotecting agent can be used. While the aforementioned deprotectingagent is not particularly limited, for example, hydrogen fluoridepyridine, hydrogen fluoride triethylamine, ammonium fluoride,hydrofluoric acid, tetrabutylammoniumfluoride and the like can bementioned. While the reaction solvent for the aforementioneddeprotection is not particularly limited, for example, ketones such asacetone and the like, ethers such as diethyl ether, THF(tetrahydrofuran) and the like, alcohols such as methanol, ethanol andthe like, nitriles such as acetonitrile etc., and the like can bementioned. While the reaction time of the aforementioned deprotection isnot particularly limited, it is, for example, 30 min-24 hr, preferably2-12 hr, more preferably 2-4 hr. While the reaction temperature of theaforementioned deprotection is not particularly limited, it is, forexample, 0 to 100° C., preferably 20 to 60° C., more preferably 20 to50° C. The concentration of the glycoside compound represented by theaforementioned chemical formula (1a) and the aforementioned deprotectingagent is not particularly limited, and can be appropriately determined.The substance amount ratio of the glycoside compound represented by theaforementioned chemical formula (1a) and the aforementioned deprotectingagent is not particularly limited and may be, for example, astoichiometric mixture ratio or any other ratio. Also, the amount ofother reaction substance to be used is not particularly limited. Thenumber of moles of the aforementioned deprotecting agent is, forexample, 0.1- to 20-fold, preferably 0.2- to 10-fold, more preferably 1-to 5-fold, relative to that of the glycoside compound represented by theaforementioned chemical formula (1a). The reaction conditions of theaforementioned deprotection may be appropriately determined by referringto, for example, the conditions of a similar deprotection in a knownglycoside compound, and the like, or by reference to any of thebelow-mentioned Examples 2 to 5.

The production method of the glycoside compound of the present inventionpreferably further includes an introduction step of a protecting groupfor introducing protecting groups R¹ and R² into the aforementionedchemical formula (1b) to produce glycoside compound represented by thefollowing chemical formula (1c). In this case, the glycoside compoundrepresented by the following chemical formula (1c) is a glycosidecompound of the aforementioned chemical formula (1) wherein R¹ and R²are except for hydrogen atoms, the aforementioned chemical formulas(R¹R²A) and (R¹R²B).

In the aforementioned chemical formula (1c),

R¹ and R² are R¹ and R² in the aforementioned chemical formula (1) butexcluding a hydrogen atom and the aforementioned chemical formulas(R¹R²A) and (R¹R²B), and

B, L¹, n and [D¹] are as defined for the aforementioned chemical formula(1).

The reaction conditions of the aforementioned protecting groupintroduction step are not particularly limited and may be appropriatelydetermined, for example, by referring to a similar reaction in a knownglycoside compound and the like. In the aforementioned protecting groupintroduction step, for example, the aforementioned R¹ and R² may besimultaneously (in one step) introduced, or R² may be added afterintroduction of R¹, or R¹ may be introduced after introduction of R².For example, it is preferable to introduce R² after introduction of R¹.While the protecting groups R¹ and R² are not particularly limited, forexample, they are as mentioned above.

In an introduction reaction of the protecting group R¹, a protectinggroup-introducing agent may be appropriately selected according to R¹.While the reaction solvent is not particularly limited, for example,polar solvents such as pyridine and the like, nitriles such asacetonitrile and the like, ethers such as tetrahydrofuran etc., and thelike can be mentioned. While the reaction time is not particularlylimited, it is, for example, 30 min-24 hr, preferably 2-12 hr, morepreferably 2-4 hr. While the reaction temperature is not particularlylimited, it is, for example, 0 to 100° C., preferably 10 to 60° C., morepreferably 20 to 30° C. The concentration of the glycoside compound tobe used and the protecting group-introducing agent is not particularlylimited, and can be appropriately determined. The substance amount ratioof the aforementioned glycoside compound and the aforementionedprotecting group-introducing agent is not particularly limited and maybe, for example, a stoichiometric mixture ratio or any other ratio.Also, the amount of other reaction substance to be used is notparticularly limited. The number of moles of the aforementionedprotecting group-introducing agent is, for example, 1- to 100-fold,preferably 1- to 20-fold, more preferably 1- to 5-fold, relative to thatof the aforementioned glycoside compound. The reaction conditions of theintroduction reaction of a protecting group R¹ may be appropriatelydetermined by referring to, for example, the conditions of a similarreaction in a known glycoside compound, and the like, or by reference toany of the below-mentioned Examples 2 to 5.

In the introduction reaction of the protecting group R², the protectinggroup-introducing agent may be appropriately selected according to R².While the reaction solvent is not particularly limited, for example,nitriles such as acetonitrile and the like, ethers such astetrahydrofuran, halogenated solvents such as dichloromethane etc., andthe like can be mentioned. While the reaction time is not particularlylimited, it is, for example, 30 min-24 hr, preferably 1-12 hr, morepreferably 4-6 hr. While the reaction temperature is not particularlylimited, it is, for example, −80 to 30° C., preferably −70 to 0° C.,more preferably −50 to −40° C. The concentration of the glycosidecompound to be used and the protecting group-introducing agent is notparticularly limited, and can be appropriately determined. The substanceamount ratio of the aforementioned glycoside compound and theaforementioned protecting group-introducing agent is not particularlylimited and may be, for example, a stoichiometric mixture ratio or anyother ratio. Also, the amount of other reaction substance to be used isnot particularly limited. The number of moles of the aforementionedprotecting group-introducing agent is, for example, 1- to 20-fold,preferably 1- to 5-fold, more preferably 1- to 1.5-fold, relative tothat of the aforementioned glycoside compound. The reaction conditionsof the introduction reaction of a protecting group R² may beappropriately determined by referring to, for example, the conditions ofa similar reaction in a known glycoside compound, and the like, or byreference to the below-mentioned Example 2 or 3.

Also, in each of the aforementioned reaction steps, the purificationmethod of the reaction product is not particularly limited and themethod can be appropriately performed by reference to a known method andthe like.

In the production method of the glycoside compound of the presentinvention, the ether represented by the aforementioned chemical formula(106) is more preferably produced by the aforementioned productionmethod of ether of the present invention. In addition, thioether (103),which is an intermediate therefor, is more preferably produced by theaforementioned first or second production method of the thioether in thepresent invention. In this way, the glycoside compound of the presentinvention can be obtained in a still higher yield.

6. Production Method of Nucleic Acid

The production method of a nucleic acid of the present invention is, asmentioned above, a production method of a nucleic acid having thestructure represented by the following chemical formula (I), andcharacteristically includes a condensation step for a condensationreaction of the glycoside compound of the present invention representedby the aforementioned chemical formula (1), wherein the glycosidecompound is a glycoside compound represented by the aforementionedchemical formula (2).

In the aforementioned chemical formula (I), B is as defined for theaforementioned chemical formula (1), (2) or (3),

R¹⁰⁰ is a hydrogen atom or a hydroxyl group,

respective B may be the same or different, and respective R¹⁰⁰ may bethe same or different, and

m is a positive integer.

The reaction conditions of the production method of a nucleic acid ofthe present invention are not particularly limited and, for example, themethod can be performed in the same manner as in general phosphoramiditemethod and the like. For example, the production method of a nucleicacid of the present invention may include production (synthesis) by ageneral automatic synthesizer of nucleic acid and the like. That is, theglycoside compound represented by the aforementioned chemical formula(2) of the present invention can be used as an amidite for an automaticnucleic acid synthesizer. Using the glycoside compound represented bythe aforementioned chemical formula (2) of the present invention, theproduction method of a nucleic acid of the present invention can producea nucleic acid with high purity and in a high yield. Specifically, forexample, RNA can be synthesized with purity comparable to that in DNAsynthesis. While the reason therefor is not clear, for example, improvedefficiency of the condensation reaction (coupling reaction) due to lesssteric hindrance during condensation reaction (coupling reaction) ascompared to TBDMS amidite, TOM amidite, ACE amidite and the like, andthe like are considered. Moreover, the glycoside compound represented bythe aforementioned chemical formula (2) of the present invention permitseasy deprotection associated with the condensation reaction (couplingreaction).

In the production method of a nucleic acid of the present invention, forexample, the nucleic acid having the structure represented by theaforementioned chemical formula (I) may be a nucleic acid represented bythe following chemical formula (II):

in the aforementioned chemical formula (II),

B, R¹⁰⁰ and m are as defined for the aforementioned chemical formula(I), respective B may be the same or different, respective R¹⁰⁰ may bethe same or different, and

Z is a hydrogen atom or a phosphate group,

and

the production method may contain the following steps A1-A6.

[Step A1]

A step of producing the glycoside compound represented by the followingchemical formula (202) by reacting an acid with the glycoside compoundrepresented by the following chemical formula (201), and deprotectingthe hydroxyl group of the 5′ position.

In the aforementioned chemical formulas (201) and (202),

m and B are as defined for the aforementioned chemical formula (II),

R¹ and R^(2c) are as defined for the aforementioned chemical formula(2),

respective R²⁰⁰ may be the same or different and each is a hydrogenatom, an acyloxy group or a substituent represented by the followingchemical formula (203),

T is a hydrogen atom, an acyloxy group, or a substituent represented bythe following chemical formula (203) or (204),

E is an acyl group or a substituent represented by the followingchemical formula (204),

at least one of E and T is a substituent represented by the followingchemical formula (204),

in the aforementioned chemical formula (203),

[D¹], L¹ and n are as defined for the aforementioned chemical formula(2),

in the aforementioned chemical formula (204),

L³ is a linker, [S] is a solid phase carrier,

Q is a single bond or a substituent represented by the followingchemical formula (205),

in the aforementioned chemical formula (205),

R^(2c) is as defined for the aforementioned chemical formula (2).

In the aforementioned chemical formulas (201) and (202), examples of theaforementioned acyl group for E include an acetyl group, a propionylgroup, a butyryl group, an isobutyryl group, a benzoyl group, a4-methoxybenzoyl group, a phenylacetyl group, a phenoxyacetyl group, a4-tert-butylphenoxyacetyl group, a 4-isopropylphenoxyacetyl group andthe like. The acyl group in the aforementioned acyloxy group for T andR²⁰⁰ is also the same.

In the aforementioned chemical formula (204), examples of theaforementioned L³ (linker) include a group induced from any of a3-aminopropyl group, a long chain alkylamino (LCAA) group and2-(2-hydroxyethylsulfonyl)ethanol, a succinyl group and the like.Examples of the aforementioned [S] (solid phase carrier) includecontrolled pore glass (CPG), oxalylated controlled pore glass (see Alulet al., Nucleic Acids Research, Vol. 19, 1527 (1991), etc.), TentaGelsupport-aminopolyethylene glycol derivatization support (see Wright etal., Tetrahedron Letters, Vol. 34, 3373 (1993), etc.), a copolymer ofporous polystyrene and divinylbenzene and the like.

In the aforementioned chemical formulas (201) and (202), preferably, Tis a substituent represented by the aforementioned chemical formula(203), and E is a compound represented by the following chemical formula(204-1) or (204-2).

In the aforementioned chemical formulas (204-1) and (204-2), LCAA andCPG are as defined for the aforementioned chemical formula (204). In theaforementioned chemical formula (204-2), [D²] is as defined for theaforementioned chemical formula (2).

While the aforementioned acid to be used for step A1 is not particularlylimited, for example, halogenated carboxylic acid and the like can bementioned. Examples of the aforementioned halogenated carboxylic acidinclude trifluoroacetic acid, dichloroacetic acid, trichloroacetic acidand the like. The aforementioned acid may be used, for example, afterdissolving in a suitable solvent. While the concentration of thesolution is not particularly limited, it is, for example, 1-5 wt %.While the aforementioned solvent is not particularly limited, forexample, halogenated solvents such as dichloromethane and the like,nitriles such as acetonitrile and the like, water and the like can bementioned. These may be used alone or plural kinds thereof may be usedin combination. While the reaction temperature in step A1 is notparticularly limited, 20° C.-50° C. is preferable. While the reactiontime is not particularly limited and varies depending on the kind of theacid to be used, reaction temperature and the like, it is, for example,1 min-1 hr. Also, while the amount of the aforementioned acid to be used(number of moles) is not particularly limited, it is, for example, 1- to100-fold, preferably 1- to 10-fold, relative to the number of moles ofthe sugar (or base) in the aforementioned glycoside compound (201).

[Step A2]

A step of producing the glycoside compound represented by the followingchemical formula (206) by condensing the glycoside compound (202)produced in the aforementioned step A1 with a nucleic acid monomercompound in the presence of an activator.

In the aforementioned chemical formula (206),

B, E, m, R¹, R²⁰⁰, T and R^(2c) are as defined for the aforementionedchemical formula (201), respective B, respective R²⁰⁰ and respectiveR^(2c) may be the same or different.

Examples of the aforementioned “nucleic acid monomer compound” in stepA2 include the glycoside compound represented by the aforementionedchemical formula (2) of the present invention. While it is possible touse other glycoside compounds as the aforementioned “nucleic acidmonomer compound”, the glycoside compound represented by theaforementioned chemical formula (2) is preferably used from the aspectsof reaction efficiency, yield of the object resultant product, purity ofthe object resultant product and the like. Moreover, the glycosidecompound represented by the aforementioned chemical formula (2) may beused along with other glycoside compound. Examples of the aforementioned“other glycoside compound” include a glycoside compound of theaforementioned chemical formula (2) wherein R³ is changed to H (hydrogenatom) or OH (hydroxyl group). In the production method of a nucleic acidof the present invention, 1 molecule or more at minimum of the glycosidecompound represented by the aforementioned chemical formula (2) of thepresent invention is used to produce a nucleic acid. As mentioned below,moreover, the condensation reaction may be repeated plural times in StepA2 by repeating steps A1-A4 appropriate times. In this way, the chainlength of the object nucleic acid (glycoside compound (I) or (II)) canbe a desired (given) chain length. In the production method of a nucleicacid of the present invention, the glycoside compound represented by theaforementioned chemical formula (2) of the present invention ispreferably subjected to plural molecule polymerization (condensationpolymerization). In this way, for example, RNA (i.e., nucleic acid ofthe aforementioned chemical formulas (I) or (II), wherein each R¹⁰⁰ is ahydroxyl group) can be synthesized (produced). Alternatively, DNA(nucleic acid of the aforementioned chemical formulas (I) or (II),wherein each R¹⁰⁰ is a hydrogen atom) can be synthesized by, forexample, reverse transcription of RNA synthesized by plural moleculepolymerization (condensation polymerization) of the glycoside compoundrepresented by the aforementioned chemical formula (2) of the presentinvention. The nucleic acid of the aforementioned chemical formulas (I)or (II), which includes R¹⁰⁰ as a hydrogen and R¹⁰⁰ as a hydroxyl groupmay be synthesized by, for example, a condensation reaction of theglycoside compound represented by the aforementioned chemical formula(2) and the glycoside compound of the aforementioned chemical formula(2) wherein R³ is changed to H (hydrogen atom).

In step A2, the aforementioned activator is not particularly limitedand, for example, may be an activator similar to that used for knownnucleic acid synthesis. Examples of the aforementioned activator include1H-tetrazole, 5-ethylthiotetrazole, 4,5-dichloroimidazole,4,5-dicyanoimidazole, benzotriazole triflate, imidazole triflate,pyridinium triflate, N,N-diisopropylethylamine,2,4,6-collidine/N-methylimidazole and the like.

In step A2, while the reaction solvent is not particularly limited, forexample, nitriles such as acetonitrile and the like, ethers such astetrahydrofuran, dioxane etc., and the like can be mentioned. Thesesolvents may be used alone or plural kinds thereof may be used incombination. While the reaction temperature is not particularly limited,20° C.-50° C. is preferable. Also, while the reaction time is notparticularly limited and varies depending on the kind of the activatorto be used, reaction temperature and the like, it is, for example, 1min-1 hr. While the amount of the aforementioned nucleic acid monomercompound to be used (number of moles) is not particularly limited, itis, for example, 1- to 100-fold, preferably 1- to 10-fold, relative tothe number of moles of the sugar (or base) in the aforementionedglycoside compound (202). The amount of the aforementioned activator tobe used is also the same.

[Step A3]

A step of capping the hydroxyl group at the 5′-position of theaforementioned glycoside compound (202), which was unreacted in theaforementioned step A2.

In the aforementioned chemical formula (207),

R³⁰⁰ is a methyl group or a phenoxymethyl group, and

B, E, m, R²⁰⁰, T and R^(2c) are as defined for the aforementionedchemical formula (5).

In step A3, the hydroxyl group at the 5′-position, which was unreactedon completion of the aforementioned step A2, is protected by reactingwith a capping agent. While the aforementioned capping agent is notparticularly limited, for example, acetic anhydride, phenoxyacetic acidanhydride and the like can be mentioned. For example, the aforementionedcapping agent may be used in the form of a solution. While the solventof the aforementioned solution is not particularly limited, for example,pyridine, dichloromethane, acetonitrile, tetrahydrofuran, a mixedsolvent thereof and the like can be mentioned. While the concentrationof the aforementioned solution is not particularly limited, it is, forexample, 0.05-1M. In step A3, for example, an appropriate reactionaccelerator such as 4-dimethylaminopyridine, N-methylimidazole and thelike may also be used in combination. While the reaction temperature isnot particularly limited, 20° C.-50° C. is preferable. Also, while thereaction time is not particularly limited and varies depending on thekind of the capping agent to be used, reaction temperature and the like,it is, for example, 1-30 min. While the amount of the aforementionedcapping agent to be used (number of moles) is not particularly limited,it is, for example, 1- to 100-fold, preferably 1- to 10-fold, relativeto the number of moles of the sugar (or base) in the aforementionedglycoside compound (202). The amount of the aforementioned activator tobe used is also the same. The amount of the aforementioned reactionaccelerator to be used is also the same.

[Step A4]

A step of converting a phosphorous acid group in the aforementionedchemical formula (206) into a phosphate group by reacting the glycosidecompound (206) produced in the aforementioned step A2 with an oxidant.

In the aforementioned chemical formula (208),

B, E, m, R¹, R²⁰⁰, T and R^(2c) are as defined for the aforementionedchemical formula (206).

While the aforementioned oxidant in step A4 is not particularly limited,for example, iodine, peroxide (e.g., tert-butyl hydroperoxide) and thelike can be mentioned. The aforementioned oxidant may be used in theform of a solution. While the solvent for the aforementioned solution isnot particularly limited, for example, pyridine, tetrahydrofuran, water,acetic acid, methylene chloride, a mixed solvent thereof and the likecan be mentioned. As the aforementioned solution, a solution obtained bydissolving iodine in a mixed solvent of water, pyridine andtetrahydrofuran, a solution obtained by dissolving iodine in a mixedsolvent of pyridine and acetic acid, a solution obtained by dissolving dperoxide in methylene chloride and the like can be used. While theconcentration of the aforementioned solvent is not particularly limited,it is, for example, 0.05-2M. While the reaction temperature is notparticularly limited, 20° C.-50° C. is preferable. Also, while thereaction time is not particularly limited and varies depending on thekind of the oxidant to be used, reaction temperature and the like, itis, for example, 1-30 min. While the amount of the aforementionedoxidant to be used (number of moles) is not particularly limited, it is,for example, 1- to 100-fold, preferably 1- to 10-fold, relative to thenumber of moles of the sugar (or base) in the aforementioned glycosidecompound (206).

After step A4 and before performing the next step A5, the operation mayreturn to step A1. By repeating steps A1-A4 an appropriate number oftimes in this way, the chain length of the object nucleic acid(glycoside compound (208)) can become a desired (given) chain length.

[Step A5]

A step of cleaving the glycoside compound (208) produced in theaforementioned step A4 from the aforementioned solid phase carrier, anddeprotecting each nucleic acid base region and the hydroxyl group ateach 2′-position.

In the aforementioned chemical formula (209),

B, m, R¹ and R²⁰⁰ are as defined for the aforementioned chemical formula(208), and

R¹⁰⁰ and Z are as defined for the aforementioned chemical formula (II).

In step A5, a step for cleaving the aforementioned glycoside compound(208), namely, a nucleic acid with a given chain length, from a solidphase carrier (cleaving step) can be performed by adding a cleavingagent to a solid carrier carrying the aforementioned nucleic acid (208).While the aforementioned cleaving agent is not particularly limited, forexample, conc. aqueous ammonia, methylamine and the like can bementioned. One kind or two or more kinds may be used in combination. Theaforementioned cleaving agent may be used by, for example, dissolving ina solvent. While the aforementioned solvent is not particularly limited,for example, water, methanol, ethanol, isopropyl alcohol, acetonitrile,tetrahydrofuran, a mixed solvent thereof and the like can be mentioned,with particular preference given to ethanol. While the concentration ofthe aforementioned solution is not particularly limited, for example,the concentration of ammonium hydroxide in the aforementioned solutionis set to 20-30 wt %. The concentration of the aforementioned ammoniumhydroxide is preferably 25-30 wt %, more preferably 28-30 wt %. Whilethe amount of the aforementioned cleaving agent to be used (number ofmoles) is not particularly limited, it is, for example, 1- to 100-fold,preferably 1- to 10-fold, relative to the number of moles of the sugar(or base) in the aforementioned glycoside compound (208). The amount ofthe aforementioned activator to be used is also the same. While thereaction temperature of the aforementioned cleaving step is notparticularly limited, it is, for example, 15° C. to 75° C., preferably15° C. to 50° C., more preferably 15° C. to 30° C., more preferably 18°C. to 25° C., more preferably 20° C. to 25° C. While the reaction timeis not particularly limited and varies depending on the kind of theoxidant, reaction temperature and the like, it is, for example, 1-24 hr.

In the aforementioned deprotection step of the hydroxyl group at the2′-position in step A5, while the deprotecting agent is not particularlylimited, for example, tetraalkylammoniumhalide can be mentioned. Morespecifically, for example, tetrabutylammoniumfluoride can be mentioned.While the solvent to be used for the aforementioned deprotection step isnot particularly limited, for example, tetrahydrofuran,N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, a mixedsolvent thereof and the like can be mentioned. In addition, thebyproducts such as acrylonitrile and the like to be developed in theaforementioned deprotection step may be trapped with, for example,alkylamine, thiol or a mixture thereof. Examples of the aforementionedalkylamine include alkylamine having a linear alkyl group having 1-10carbon atoms. Examples of the aforementioned thiol include alkylthiolhaving a linear alkyl group having 1-10 carbon atoms. While the reactiontime and reaction temperature of the aforementioned deprotection stepare not particularly limited, 30 min-50 hr and 10 to 70° C. arepreferable. The amount of the aforementioned deprotecting agent to beused is, for example, 10- to 1000-fold, preferably 50- to 200-fold,relative to the number of moles of the sugar (or base) in theaforementioned glycoside compound (202). The amount of theaforementioned trapping agents to be used is also the same. In addition,the method for separating and purifying the glycoside compound (209),which is the object product, from the reaction mixture of theaforementioned deprotection step is not particularly limited, and aconventional purification method can be used. Examples of theaforementioned purification method include filtration, elution,concentration, neutralization, centrifugation, chromatography (silicagel column, thin layer, reversed-phase ODS, ion exchange, gelfiltration), dialysis, ultrafiltration and the like. These may be usedalone or plural kinds thereof may be used in combination.

[Step A6]

A step of removing the hydroxyl-protecting group at the 5′-position ofthe compound (209) produced in the aforementioned step A5.

While the aforementioned acid to be used for step A6 is not particularlylimited, for example, halogenated carboxylic acid, carboxylic acid andthe like can be mentioned. Examples of the aforementioned halogenatedcarboxylic acid or carboxylic acid include trifluoroacetic acid,dichloroacetic acid, trichloroacetic acid, acetic acid and the like. Theaforementioned acid may be used, for example, after dissolving in asuitable solvent. While the concentration of the solution is notparticularly limited, it is, for example, 10-70 wt %. While theaforementioned solvent is not particularly limited, for example,dichloromethane, acetonitrile, chloroform, ethanol, water, buffer havingpH 2-5, a mixed solvent thereof and the like can be mentioned. Examplesof the aforementioned buffer include acetate buffer. While the reactiontemperature in step A6 is not particularly limited, 10° C.-60° C. ispreferable. While the reaction time is not particularly limited andvaries depending on the kind of the acid to be used, reactiontemperature and the like, it is, for example, 1 min-30 min. While theamount of the aforementioned acid to be used (number of moles) is notparticularly limited, it is, for example, 1- to 200-fold, preferably 1-to 20-fold, relative to the number of moles of the sugar (or base) inthe aforementioned glycoside compound (209).

The aforementioned compound (II), which is the object product of theaforementioned step A6, may be separated and purified as necessary. The“separation” includes, for example, isolation. The separation andpurification method is not particularly limited and, for example,extraction, concentration, neutralization, filtration, centrifugation,reversed-phase column chromatography, ion exchange columnchromatography, gel filtration column chromatography, high performanceliquid chromatography, dialysis, ultrafiltration and the like can bementioned, which may be used alone or plural kinds thereof may be usedin combination.

The order of step A5 and the aforementioned step A6 may be reversed.That is, the aforementioned step A6 may be performed after theaforementioned step A4 and before the aforementioned step A5, afterwhich the aforementioned step A5 may be performed.

Use of the nucleic acid produced by the production method of a nucleicacid of the present invention is not particularly limited and, forexample, it is similar to that of known nucleic acids. Since theaforementioned nucleic acid can be produced at a low cost and with highpurity when produced by the production method of a nucleic acid of thepresent invention, use thereof is broad and, for example, it is suitablefor use in the production of a medicament and the like.

While the present invention is explained in detail in the following byreferring to Examples and the like, the present invention is not limitedby them.

EXAMPLES Example 1 Synthesis of EMM Reagent (1004)

According to the following scheme E1, an EMM reagent (1004) wassynthesized. “EMM” stands for “cyanoethoxymethoxymethyl” (hereinafterthe same).

[1] Synthesis of bis(chloromethyl)ether (1002)

A mixture of para-formaldehyde (1001) (100 g, 3.33 mol) and concentratedhydrochloric acid (70 mL, 0.83 mol) was stirred at −5° C. to 0° C. for30 min. Chlorosulfonic acid (190 mL, 2.86 mol) was added dropwise to thereaction mixture over 4 hr. The mixture was further stirred at −5° C. to0° C. for 3 hr and further at room temperature overnight. The upperlayer of the reaction mixture was separated using a partitioning funneland washed with ice water. The reaction mixture after washing was addedinto an Erlenmeyer flask containing ice, and cooled in an ice bath.While vigorously stirring the solution, 40% aqueous sodium hydroxidesolution was slowly added until the aqueous layer became strong alkali(pH 11). The resultant product was separated by a partitioning funnel,and dried by adding potassium carbonate and potassium hydroxide in anice bath. The desiccant was removed by filtration to give the objectcompound (1002) as a colorless oil (158 g, yield 83%). Reference wasmade to Saul R. Buc, Org. Synth., Coll. Vol. 4, p. 101 (1963); Vol. 36,p. 1 (1956) for the operation for the synthesis. The instrumentalanalysis value of the compound (1002) is shown below.

Compound (1002):

¹H-NMR (400 MHz, CDCl₃) δ: 5.55 (4H, s).

[2] Synthesis of bis(methylthiomethyl)ether (1003)

Methylthiosodium•4.5 hydrate (330 g, 2.17 mol) was added to a solutionof bis(chloromethyl)ether (1002) (50 g, 0.43 mol) in acetone (720 ml),and the mixture was vigorously stirred at room temperature for 1 hr. Thereaction solution was filtered through celite, and the filtrate wasconcentrated under reduced pressure. Dichloromethane was added, and themixture was washed three times with saturated aqueous sodium hydrogencarbonate solution and once with saturated aqueous sodium chloridesolution. The organic layer was dried over anhydrous sodium sulfate andconcentrated under reduced pressure. The crude product was evaporatedunder reduced pressure (70-84° C., 20-22 mmHg (2.7-2.9 kPa)) to give theobject compound (1003) as a colorless oil (43.7 g, yield 74%). Thissynthesis method is an improved synthesis method of the synthesis methoddescribed in Eur. Pat. Appl. (1994), EP604910A1 to further improve theyield of the object compound (yield 48% described in the aforementioneddocument). The instrumental analysis value of the compound (1003) isshown below.

Compound (1003):

¹H-NMR (400 MHz, CDCl₃) δ: 4.77 (4H, s), 2.16 (6H, s).

[3] Synthesis of EMM Reagent (1004)

Bis(methylthiomethyl)ether (1003) (10.0 g, 72 mmol) was dissolved intetrahydrofuran (100 ml) under an argon atmosphere. Cyanoethanol (2.6 g,36 mmol) and molecular sieves 4A (10 g) were added to the solution, andthe mixture was stirred for 10 min. N-iodosuccinimide (9.8 g, 43 mmol)was further added and dissolved in the mixture, and the mixture wascooled to 0° C. After cooling, trifluoromethanesulfone acid silver (0.28g, 1.1 mmol) was added, and the mixture was stirred for 1 hr. Afterstirring, ethyl acetate was added, and the mixture was washed withsaturated aqueous sodium thiosulfate solution, saturated aqueous sodiumhydrogen carbonate solution and saturated aqueous sodium chloridesolution in this order. Thereafter, the organic layer was separated,dried over anhydrous sodium sulfate, and concentrated under reducedpressure. The crude product was purified by silica gel columnchromatography (hexane:ethyl acetate=4:1) to give the object compound(1004) as a colorless oil (3.4 g, yield 58%). The instrumental analysisvalue of the compound (1004) is shown below.

Compound (1004):

¹H-NMR (400 MHz, CDCl₃) δ: 4.86 (2H, s), 4.73 (2H, s), 3.80 (2H, t,J=6.3 Hz), 2.64 (2H, t, J=6.3 Hz), 2.18 (3H, s).

GC-MS (EI+): m/z 161[M]⁺, 84 [CH₂—O—(CH₂)₂CN]⁺, 61[CH₃SCH₂]⁺,54[(CH₂)₂CN]⁺

Example 2 Synthesis of Uridine EMM Amidite (1009)

According to the following scheme E2, uridine EMM amidite (1009) wassynthesized.

[1] Synthesis of3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-2′-O-(2-cyanoethoxymethoxymethyl)uridine(1006)

3′,5′-O-(Tetraisopropyldisiloxane-1,3-diyl)uridine (1005) (0.50 g, 1.0mmol) was dissolved in tetrahydrofuran (5 mL) under an argon atmosphere,the EMM reagent (1004) (0.26 g, 1.6 mmol) was further added, and themixture was stirred. After cooling this to −45° C.,trifluoromethanesulfonic acid (0.24 g, 1.6 mmol) was added, and themixture was stirred for 10 min. After stirring, N-iodosuccinimide (0.36g, 1.6 mmol) was added, and the mixture was further stirred for 5 hr.After completion of the reaction, triethylamine was added to quench thereaction. Ethyl acetate was further added, and the mixture was washedtwice with saturated aqueous sodium thiosulfate solution and once withsaturated aqueous sodium chloride solution. The organic layer was driedover anhydrous sodium sulfate and concentrated under reduced pressure.Ethyl acetate was added to the residue, and the mixture was washed oncewith saturated aqueous sodium thiosulfate solution and once withsaturated aqueous sodium chloride solution. The organic layer was driedover anhydrous sodium sulfate and concentrated under reduced pressure.The obtained crude product was purified by silica gel columnchromatography (ethyl acetate:hexane=1:1) to give the object compound(1006) (0.51 g, yield 83%). The instrumental analysis value of thecompound (1006) is shown below.

Compound (1006):

¹H-NMR (400 MHz, CDCl₃) δ: 8.41 (1H, s), 7.90 (1H, d, J=7.8 Hz), 5.72(1H, s), 5.67 (1H, d, J=8.3 Hz), 5.15-5.08 (2H, m), 4.98 (1H, d, J=6.8Hz), 4.84 (1H, d, J=4.4 Hz), 4.26-4.11 (4H, m), 4.04-3.97 (2H, m),3.90-3.78 (1H, m), 2.70-2.65 (2H, m), 1.11-0.94 (28H, m).

[2] Synthesis of 2′-O-(2-cyanoethoxymethoxymethyl)uridine (1007)

3′,5′-O-(Tetraisopropyldisiloxane-1,3-diyl)-2″-O-(2-cyanoethoxymethoxymethyl)uridine(1006) (3.8 g, 6.3 mmol) was dissolved in tetrahydrofuran (15 mL),hydrogen fluoride pyridine (1.6 g, 16 mmol) was further added, and themixture was stirred at room temperature overnight. The obtainedprecipitate was collected by filtration and dried under reduced pressureto give the aforementioned precipitate (1.6 g). On the other hand,toluene was added to the residual filtrate and the supernatant wasremoved by decantation. To the solution after removal of the supernatantwas added diisopropylether, the supernatant was removed by decantation,and this operation was repeated until crystals were obtained. Theobtained precipitate (crystal) was collected by filtration and driedunder reduced pressure to give the aforementioned precipitate (crystal)(0.5 g). The respective aforementioned precipitates were combined togive the object compound (1007) (2.1 g, yield 92%). The instrumentalanalysis value of the compound (1007) is shown below.

Compound (1007):

¹H-NMR (400 MHz, CDCl₃) δ: 10.23 (1H, br.s), 7.90 (1H, d, J=7.8 Hz),5.84 (1H, d, J=2.9 Hz), 5.59 (1H, d, J=8.3 Hz), 5.09 (1H, d, J=7.0 Hz),4.98 (1H, d, J=6.7 Hz), 4.87 (2H, s), 4.25-4.22 (3H, m), 3.99 (1H, s),3.83-3.69 (5H, m), 2.70-2.61 (2H, m).

[3] Synthesis of5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)uridine(1008)

2′-O-(2-Cyanoethoxymethoxymethyl)uridine (1007) (2.1 g, 6.0 mmol) wasazeotropically distilled with pyridine, and the solvent was evaporatedby a vacuum pump. This operation was performed three times. Thereafter,4,4′-dimethoxytrityl chloride (2.6 g, 7.2 mmol) and pyridine (10 mL)were added, and the mixture was stirred for 2 hr. After stirring,dichloromethane was added, and the mixture was washed twice withsaturated aqueous sodium hydrogen carbonate solution and successivelyonce with saturated aqueous sodium chloride solution. The organic layerwas dried over anhydrous sodium sulfate and concentrated under reducedpressure. The obtained crude product was purified by silica gel columnchromatography (acetone:hexane=3:7, containing 0.05%pyridine→dichloromethane:methanol=9:1, containing 0.05% pyridine) togive the object compound (1008) (3.8 g, yield 96%). The instrumentalanalysis value of the compound (1008) is shown below.

Compound (1008):

¹H-NMR (400 MHz, CDCl₃) δ: 8.62 (1H, br.s), 7.99 (1H, d, J=7.8 Hz),7.40-7.25 (9H, m), 6.90-6.84 (4H, m), 5.96 (1H, d, J=2.0 Hz), 5.28 (1H,d, J=8.3 Hz), 5.18 (1H, d, J=6.8 Hz), 5.03 (1H, d, J=7.3 Hz), 4.87 (2H,d, J=7.3 Hz), 4.48 (1H, q, J=5.4 Hz), 4.29 (1H, dd, J=5.1, 2.2 Hz),4.11-4.07 (1H, m), 3.87 (2H, t, J=6.0 Hz), 3.84 (6H, s), 3.55 (2H, dd,J=9.0, 2.2 Hz), 2.76 (1H, d, J=7.8 Hz), 2.65 (2H, t, J=6.6 Hz).

[4] Synthesis of5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)uridine3′-O-(2-cyanoethyl N,N-diisopropylphosphoramidite) (1009)

5′-O-(4,4′-Dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)uridine(1008) (3.7 g, 5.6 mmol) was azeotropically distilled with pyridine, andthe solvent was evaporated by a vacuum pump. This operation wasperformed three times. Furthermore, under an argon atmosphere,diisopropylammonium tetrazolide (1.2 g, 6.8 mmol) and acetonitrile (10mL) were added. 2-Cyanoethyl-N,N,N′,N′-tetraisopropyl phosphorodiamidite(2.0 g, 6.8 mmol) dissolved in acetonitrile (20 mL) was added to thereaction solution, and the mixture was stirred at 45° C. for 2 hr.Furthermore, dichloromethane was added, and the mixture was washed oncewith saturated aqueous sodium hydrogen carbonate solution and once withsaturated aqueous sodium chloride solution. The organic layer afterwashing was dried over anhydrous sodium sulfate and concentrated underreduced pressure. The obtained crude product was purified by silica gelcolumn chromatography (acetone:hexane=1:1, containing 0.05% pyridine) togive the object compound (1009) (4.3 g, yield 89%). The instrumentalanalysis value of the compound (1009) is shown below.

Compound (1009):

³¹P-NMR (162 MHz, CDCl₃) δ: 153.5, 151.9.

MS (FAB+): m/z 882[M+Na]⁺

Example 3 Synthesis of Cytosine EMM Amidite (1014)

According to the following scheme E3, cytosine EMM amidite (1014) wassynthesized.

[1] Synthesis ofN⁴-acetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-2′-O-(2-cyanoethoxymethoxymethyl)cytidine(1011)

N⁴-Acetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)cytidine (1010)(3.0 g, 5.7 mmol) was azeotropically distilled with toluene, and thesolvent was evaporated by a vacuum pump. This operation was performedthree times. The thus-obtained mixture was dissolved in tetrahydrofuran(30 ml) under an argon atmosphere, the EMM reagent (1004) (2.8 g, 18mmol) was added, and the mixture was stirred. The mixture was cooled to−45° C., trifluoromethane sulfonic acid (1.3 g, 8.8 mmol) was added, andthe mixture was stirred for 10 min. Furthermore, N-iodosuccinimide (2.0g, 9.0 mmol) was added, and the mixture was stirred for 5 hr. Aftercompletion of the reaction, triethylamine was added to quench thereaction. Furthermore, ethyl acetate was added, and the mixture waswashed twice with saturated aqueous sodium thiosulfate solution and oncewith saturated aqueous sodium chloride solution. The organic layer afterwashing was dried over anhydrous sodium sulfate and concentrated underreduced pressure. Ethyl acetate was added to the obtained residue, andthe mixture was washed once with saturated aqueous sodium thiosulfatesolution and once with saturated aqueous sodium chloride solution. Theorganic layer after washing was dried over anhydrous sodium sulfate andconcentrated under reduced pressure to give the object compound (1011)(5.3 g, crude product). The instrumental analysis value of the compound(1011) is shown below.

Compound (1011):

¹H-NMR (400 MHz, CDCl₃) δ: 9.17 (1H, s), 8.30 (1H, d, J=7.2 Hz), 7.41(1H, d, J=7.8 Hz), 5.79 (1H, s), 5.18 (1H, d, J=6.8 Hz), 5.03 (d, 1H,J=7.4 Hz), 4.29 (1H, d, J=13.7 Hz), 4.23-4.10 (5H, m), 4.03-3.96 (2H,m), 3.87-3.75 (1H, m), 2.76-2.65 (2H, m), 2.24 (3H, s), 1.11-0.89 (28H,m).

[2] Synthesis of N⁴-acetyl-2′-O-(2-cyanoethoxymethoxymethyl)cytidine(1012)

N⁴-Acetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-2′-O-(2-cyanoethoxymethoxymethyl)cytidine(1011) (5.2 g, 8.1 mmol) was dissolved in tetrahydrofuran (30 mL) underan argon atmosphere. To the solution was added triethylaminehydrogentrifluoride (1.6 g, 9.7 mmol), and the mixture was stirred at 45° C. for1 hr. After stirring, the mixture was allowed to cool to roomtemperature, and the precipitated sediment was collected by filtration.The sediment was washed with tetrahydrofuran and dried under reducedpressure to give the object compound (1012) (1.5 g, yield 68%). Theinstrumental analysis value of the compound (1012) is shown below.

Compound (1012):

¹H-NMR (400 MHz, D₂O) δ: 8.24 (1H, d, J=7.3 Hz), 7.24 (1H, J=7.8 Hz),5.92 (1H, d, J=2.4 Hz), 5.02 (1H, d, J=6.8 Hz), 4.89 (1H, d, J=6.8 Hz),4.79-4.74 (2H, m), 4.29 (1H, dd, J=4.9, 2.9 Hz), 4.17 (1H, t, J=6.3 Hz),4.09-4.05 (1.0H, m), 3.90-3.85 (1H, m), 3.77-3.70 (3H, m), 2.67 (2H, t,J=6.1 Hz), 2.12 (3H, s).

[3] Synthesis ofN⁴-acetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)cytidine(1013)

N⁴-Acetyl-2′-O-(2-cyanoethoxymethoxymethyl)cytidine (1012) (0.70 g, 1.8mmol) was azeotropically distilled with pyridine, and the solvent wasevaporated by a vacuum pump. This operation was performed three times.Furthermore, 4,4′-dimethoxytrityl chloride (0.91 g, 2.7 mmol) andpyridine (10 mL) were added, and the mixture was stirred for 4 hr. Aftercompletion of the reaction, methanol was added, and the mixture wasconcentrated under reduced pressure. Dichloromethane was added to theresidue and the mixture was washed twice with saturated aqueous sodiumhydrogen carbonate solution and once with saturated aqueous sodiumchloride solution. The organic layer after washing was dried overanhydrous sodium sulfate and concentrated under reduced pressure. Theobtained crude product was purified by silica gel column chromatography(ethyl acetate:acetone:hexane=1:1:1, containing 0.05% pyridine→1:1:0,containing 0.05% pyridine) to give the object compound (1013) (1.1 g,yield 87%). The instrumental analysis value of the compound (1013) isshown below.

Compound (1013):

¹H-NMR (400 MHz, CDCl₃) δ: 8.61 (1H, br.s), 8.49 (1H, d, J=7.8 Hz),7.42-7.26 (9H, m), 7.09 (1H, d, J=7.3 Hz), 6.88-6.86 (4H, m), 5.94 (1H,s), 5.35 (1H, d, J=6.8 Hz), 5.11 (1H, d, J=6.8 Hz), 4.92 (1H, d, J=7.3Hz), 4.87 (1H, d, J=7.3 Hz), 4.49-4.40 (1H, m), 4.29 (1H, d, J=4.9 Hz),4.15-4.08 (1H, m), 3.86 (t, 2H, J=6.2 Hz), 3.82 (s, 6H), 3.63 (dd, 1H,J=10.6, 2.6 Hz), 3.55 (dd, 1H, J=10.6, 2.6 Hz), 2.64 (2H, t, J=6.3 Hz),2.56 (d, 1H, J=8.8 Hz), 2.21 (3H, s).

[4] Synthesis ofN⁴-acetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)cytidine3′-O-(2-cyanoethyl N,N-diisopropylphosphoramidite) (1014)

N⁴-Acetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)cytidine(1013) (1.0 g, 1.4 mmol) was azeotropically distilled with acetonitrile,and the solvent was evaporated by a vacuum pump. This operation wasperformed three times. Furthermore, under an argon atmosphere,diisopropylammonium tetrazolide (0.27 g, 1.6 mmol) and acetonitrile (4mL) were added. 2-Cyanoethyl-N,N,N′,N′-tetraisopropyl phosphorodiamidite(0.63 g, 2.1 mmol) dissolved in acetonitrile (1.5 mL) was added to thereaction solution, and the mixture was stirred at 45° C. for 3 hr. Afterstirring, dichloromethane was added, and the mixture was washed oncewith saturated aqueous sodium hydrogen carbonate solution and once withsaturated aqueous sodium chloride solution. The organic layer afterwashing was dried over anhydrous sodium sulfate and concentrated underreduced pressure. The obtained crude product was purified by silica gelcolumn chromatography (acetone:hexane:isopropyl acetate=1:2:1,containing 0.1% triethylamine→acetone:hexane:ethyl acetate=1:1:1,containing 0.1% triethylamine) to give the object compound (1014) (0.9g, yield 71%). The instrumental analysis value of the compound (1014) isshown below.

Compound (1014):

³¹P-NMR (162 MHz, CDCl₃) δ: 153.6, 151.5.

MS (FAB+): m/z 923[M+Na]⁺

Example 4 Synthesis of Adenosine EMM Amidite (1019)

According to the following scheme E4, adenosine EMM amidite (1019) wassynthesized.

[1] Synthesis ofN⁶-acetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-2′-O-(2-cyanoethoxymethoxymethyl)adenosine(1016)

Toluene was added toN⁶-acetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)adenosine (1015)(3.0 g, 5.4 mmol), and the solvent was evaporated by a vacuum pump. Thisoperation was performed three times, and water was azeotropicallydistilled away. The thus-obtained mixture was dissolved intetrahydrofuran (30 mL) under an argon atmosphere, the EMM reagent(1004) (2.6 g, 16 mmol) was added, and the mixture was stirred andcooled to −45° C. Trifluoromethanesulfonic acid (2.4 g, 16 mmol) wasadded, and the mixture was stirred for 10 min. After stirring,N-iodosuccinimide (3.7 g, 16 mmol) was added, and the mixture wasstirred for 5 hr. After completion of the reaction, triethylamine wasadded to quench the reaction. Furthermore, ethyl acetate was added, andthe mixture was washed twice with saturated aqueous sodium thiosulfatesolution, twice with saturated aqueous sodium hydrogen carbonatesolution, and once with saturated aqueous sodium chloride solution. Theorganic layer was dried over anhydrous sodium sulfate and concentratedunder reduced pressure. Ethyl acetate was added to the residue, and themixture was washed once with saturated aqueous sodium thiosulfatesolution and once with saturated aqueous sodium chloride solution. Theorganic layer was dried over anhydrous sodium sulfate and concentratedunder reduced pressure to give the object compound (1016) (8.6 g, crudeproduct). The instrumental analysis value of the compound (1016) isshown below.

Compound (1016):

¹H-NMR (400 MHz, CDCl₃) δ: 8.68 (1H, s), 8.66 (1H, s), 8.33 (1H, s),6.12 (1H, s), 5.08 (1H, d, J=7.0 Hz), 4.91-4.80 (3H, m), 4.67 (1H, d,J=7.8 Hz), 4.52 (1H, d, J=4.3 Hz), 4.25 (1H, d, J=13.0 Hz), 4.17 (1H, d,J=9.4 Hz), 4.09-4.02 (2H, m), 3.89-3.80 (1H, m), 2.67 (2H, m), 2.63 (3H,s), 1.11-0.98 (28H, m).

[2] Synthesis of N⁶-acetyl-2′-O-(2-cyanoethoxymethoxymethyl)adenosine(1017)

N⁶-Acetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-2′-O-(2-cyanoethoxymethoxymethyl)adenosine(1016) (8.2 g, 13 mmol) was dissolved in tetrahydrofuran (40 mL) underan argon atmosphere. Triethylamine hydrogen trifluoride (2.4 g, 15 mmol)was added to the solution, and the mixture was stirred at 45° C. for 2hr. The mixture was allowed to cool to room temperature, and theprecipitated sediment was collected by filtration. The sediment waswashed with tetrahydrofuran and dried under reduced pressure to give theobject compound (1017) (1.2 g, yield 52%) from the primary crystalsalone. The instrumental analysis value of the compound (1017) is shownbelow.

Compound (1017):

¹H-NMR (400 MHz, DMSO-d₆) δ: 10.71 (1H, s), 8.71 (1H, s), 8.66 (1H, s),6.17 (1H, d, J=5.8 Hz), 5.41 (1H, d, J=5.4 Hz), 5.20 (2H, m), 4.80-4.73(3H, m), 4.65-4.60 (2H, m), 4.37-4.33 (1H, m), 4.00-4.01 (1H, m),3.73-3.64 (1H, m), 3.61-3.51 (2H, m), 2.79-2.64 (2H, m), 2.22 (3H, s).

[3] Synthesis ofN⁶-acetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)adenosine(1018)

N⁶-Acetyl-2′-O-(2-cyanoethoxymethoxymethyl)adenosine (1017) (1.0 g, 2.4mmol) was azeotropically distilled with pyridine, and the solvent wasevaporated by a vacuum pump. This operation was performed three times.Thereafter, 4,4′-dimethoxytrityl chloride (0.96 g, 2.8 mmol) andpyridine (10 mL) were added, and the mixture was stirred for 3 hr. Aftercompletion of the reaction, methanol was added, the mixture wasconcentrated under reduced pressure, and dichloromethane was added tothe residue. The obtained solution was washed twice with saturatedaqueous sodium hydrogen carbonate solution and once with saturatedaqueous sodium chloride solution. The organic layer was dried overanhydrous sodium sulfate and concentrated under reduced pressure. Theobtained crude product was purified by silica gel column chromatography(acetone:hexane:ethyl acetate=1:2:2, containing 0.05% pyridine→1:1:1,containing 0.05% pyridine) to give the object compound (1018) (1.3 g,yield 76%). The instrumental analysis value of the compound (1018) isshown below.

Compound (1018):

¹H-NMR (400 MHz, CDCl₃) δ: 8.62-8.58 (2H, m), 8.17 (1H, s), 7.46-7.39(2H, m), 7.37-7.20 (7H, m), 6.87-6.79 (4H, m), 6.20 (1H, d, J=4.9 Hz),5.03-4.75 (3H, m), 4.52 (1H, s), 4.30-4.23 (1H, m), 4.12 (2H, d, J=7.3Hz), 3.79 (6H, s), 3.79-3.69 (2H, m), 3.52-3.44 (2H, m), 2.61 (3H, s),2.58 (1H, d, J=5.5 Hz), 2.51 (2H, t, J=5.9 Hz).

[4] Synthesis ofN⁶-acetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)adenosine3′-O-(2-cyanoethyl N,N-diisopropylphosphoramidite) (1019)

N⁶-Acetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)adenosine(1018) (1.0 g, 1.4 mmol) was azeotropically distilled with pyridine, andthe solvent was evaporated by a vacuum pump. This operation wasperformed three times. Furthermore, under an argon atmosphere,diisopropylammonium tetrazolide (0.31 g, 1.8 mmol) and acetonitrile (3mL) were added. 2-Cyanoethyl-N,N,N′,N′-tetraisopropyl phosphorodiamidite(0.54 g, 1.8 mmol) dissolved in acetonitrile (1 ml) was added to thereaction solution, and the mixture was stirred at 40° C. for 4 hr.Furthermore, dichloromethane was added, and the mixture was washed oncewith saturated aqueous sodium hydrogen carbonate solution and once withsaturated aqueous sodium chloride solution. The organic layer afterwashing was dried over anhydrous sodium sulfate and concentrated underreduced pressure. The obtained crude product was purified by silica gelcolumn chromatography (acetone:hexane:ethyl acetate=2:2:1, containing0.1% triethylamine) to give the object compound (1019) (1.1 g, yield73%). The instrumental analysis value of the compound (1019) is shownbelow.

Compound (1019):

³¹P-NMR (162 MHz, CDCl₃) δ: 152.7, 152.6.

MS (FAB+): m/z 947[M+Na]⁺, 925[M+H]⁺

Example 5 Synthesis of Guanosine EMM Amidite (1024)

According to the following scheme E5, guanosine EMM amidite (1024) wassynthesized.

[1] Synthesis ofN²-phenoxyacetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-2′-O-(2-cyanoethoxymethoxymethyl)guanosine(1021)

N²-Phenoxyacetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)guanosine(1020) (3.5 g, 5.3 mmol) was dissolved in tetrahydrofuran, toluene wasadded, and the solvent was evaporated by a vacuum pump. This operationwas performed three times, and water was azeotropically distilled away.The thus-obtained mixture was dissolved in tetrahydrofuran (30 mL) underan argon atmosphere, and the EMM reagent (1004) (2.6 g, 16 mmol) wasadded. The mixture was stirred and cooled to −45° C.,trifluoromethanesulfonic acid (2.4 g, 16 mmol) was added, and themixture was stirred for 10 min. Thereafter, N-iodosuccinimide (3.6 g, 16mmol) was added, and the mixture was further stirred for 5 hr. Aftercompletion of the reaction, triethylamine was added to quench thereaction. Furthermore, ethyl acetate was added, and the mixture waswashed twice with saturated aqueous sodium thiosulfate solution, twicewith saturated aqueous sodium hydrogen carbonate solution, and once withsaturated aqueous sodium chloride solution. The organic layer afterwashing was dried over anhydrous sodium sulfate and concentrated underreduced pressure. Ethyl acetate was added to the obtained residue, andthe mixture was washed once with saturated aqueous sodium thiosulfatesolution and once with saturated aqueous sodium chloride solution. Theorganic layer was dried over anhydrous sodium sulfate and concentratedunder reduced pressure to give the object compound (1021) (8.2 g, crudeproduct). The instrumental analysis value of the compound (1021) isshown below.

Compound (1021):

¹H-NMR (400 MHz, CDCl₃) δ: 11.79 (1H, s), 9.11 (1H, s), 8.04 (1H, s),7.41-7.34 (2H, m), 7.13-6.97 (3H, m), 5.94 (1H, s), 5.08, 4.97 (2H, 2d,J=7.2 Hz), 4.87-4.67 (2H, m), 4.51-4.46 (1H, dd, J=9.3, 4.9 Hz),4.33-4.24 (2H, m), 4.15 (1H, d, J=9.3 Hz), 4.02 (1H, dd, J=13.2, 2.4Hz), 3.77-3.71 (2H, m), 2.76-2.53 (2H, m), 1.11-0.94 (28H, m).

[2] Synthesis ofN²-phenoxyacetyl-2′-O-(2-cyanoethoxymethoxymethyl)guanosine (1022)

N²-Phenoxyacetyl-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-2′-O-(2-cyanoethoxymethoxymethyl)guanosine(1021) (8.0 g, 10 mmol) was dissolved in tetrahydrofuran (40 mL) underan argon atmosphere. Triethylamine hydrogen trifluoride (2.0 g, 12 mmol)was added, and the mixture was stirred at 35° C. for 2 hr. Toluene wasadded to the filtrate, and the mixture was decanted. Diethylether wasadded, and the mixture was decanted. This operation was repeated untilcrystals were obtained. The precipitate was collected by filtration anddried under reduced pressure to give the object compound (1022) (0.90 g,yield 38%) from the primary crystals alone. The instrumental analysisvalue of the compound (1022) is shown below.

Compound (1022):

¹H-NMR (400 MHz, DMSO-d₆) δ: 11.78 (2H, br.s), 8.32 (1H, s), 7.41-7.31(2H, m), 7.07-6.98 (3H, m), 6.00 (1H, d, J=5.8 Hz), 5.37 (1H, s), 5.18(1H, s), 4.88 (2H, s), 4.85-4.78 (2H, m), 4.72-4.59 (3H, m), 4.34 (1H,m), 4.00 (1H, m), 3.75-3.56 (3H, m), 2.79-2.69 (2H, m).

[3] Synthesis ofN²-phenoxyacetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)guanosine(1023)

N²-Phenoxyacetyl-2′-O-(2-cyanoethoxymethoxymethyl)guanosine (1022) (0.70g, 1.3 mmol) was azeotropically distilled with pyridine, and the solventwas evaporated by a vacuum pump. This operation was performed threetimes. The thus-obtained mixture was dissolved in pyridine (7 mL) andtetrahydrofuran (7 mL) under an argon atmosphere, molecular sieves 4 Awas added, and the mixture was stirred for 10 min. Thereafter,4,4′-dimethoxytrityl chloride (0.54 g, 1.6 mmol) was added, and themixture was further stirred for 4 hr. After completion of the reaction,dichloromethane was added, and the mixture was washed twice withsaturated aqueous sodium hydrogen carbonate solution and once withsaturated aqueous sodium chloride solution. The organic layer afterwashing was dried over anhydrous sodium sulfate and concentrated underreduced pressure. The obtained crude product was purified by silica gelcolumn chromatography (dichloromethane:acetonitrile:methanol=300:100:8,containing 0.05% pyridine) to give the object compound (1023) (0.80 g,yield 73%). The instrumental analysis value of the compound (1023) isshown below.

Compound (1023):

¹H-NMR (400 MHz, CDCl₃) δ: 11.82 (1H, s), 8.63 (1H, s), 7.84 (1H, s),7.43-7.21 (9H, m), 6.86-6.82 (4H, m), 6.06 (1H, d, J=5.9 Hz), 4.95 (1H,t, J=5.7 Hz), 4.78 (2H, m), 4.67-4.63 (2H, m), 4.50-4.45 (1H, m),4.30-4.26 (1H, m), 3.81 (6H, s), 3.79-3.67 (2H, m), 3.44 (2H, dd,J=10.6, 3.7 Hz), 2.91 (1H, s), 2.64-2.56 (2H, m), 1.66 (3H, s).

[4] Synthesis of5N²-phenoxyacetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)guanosine3′-O-(2-cyanoethyl N,N-diisopropylphosphoramidite) (1024)

N²-Phenoxyacetyl-5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)guanosine(1023) (0.70 g, 0.84 mmol) was azeotropically distilled with pyridine,and the solvent was evaporated by a vacuum pump. This operation wasperformed three times. To the thus-obtained mixture were addeddiisopropylammonium tetrazolide (0.16 g, 0.92 mmol) and acetonitrile (2mL) under an argon atmosphere. 2-Cyanoethyl-N,N,N′,N′-tetraisopropylphosphorodiamidite (0.51 g, 1.7 mmol) dissolved in acetonitrile (1 ml)was added to the reaction solution, and the mixture was stirred at 40°C. for 5 hr. After stirring, dichloromethane was added, and the mixturewas washed once with saturated aqueous sodium hydrogen carbonatesolution and once with saturated aqueous sodium chloride solution. Theorganic layer after washing was dried over anhydrous sodium sulfate andconcentrated under reduced pressure. The obtained crude product waspurified by silica gel column chromatography (ethylacetate:acetonitrile=40:1, containing 0.1% triethylamine) to give theobject compound (1024) (0.56 g, yield 65%). The instrumental analysisvalue of the compound (1024) is shown below.

Compound (1024):

³¹P-NMR (162 MHz, CDCl₃) δ: 152.7, 152.6.

MS (FAB+): m/z 1055[M+Na]⁺, 1033[M+H]⁺

Example 6 Synthesis of Uridine 40-mer (U40mer) Using Uridine EMM Amidite(1009)

Using the uridine EMM amidite (1009) synthesized in Example 2 and anucleic acid automatic synthesizer (Expedite 8909 DNA/RNA synthesizer:trade name of Applied Biosystems), an uridine 40-mer shown by thesequence of the following SEQ ID NO: 1 was synthesized.

(SEQ ID NO: 1) 5′-UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU-3′

For the synthesis of the uridine 40-mer in this Example, a CPG solidphase carrier wherein2′-O-tert-butyldimethylsilyl-5′-O-(4,4′-dimethoxytrityl)uridine islinked by a linker was used as a solid phase carrier. Furthermore,5′-O-(4,4′-dimethoxytrityl)-2′-O-(2-cyanoethoxymethoxymethyl)uridine3′-O-(2-cyanoethyl N,N-diisopropylphosphoramidite), i.e., uridine EMMamidite (1009), was used as a nucleic acid monomer compound,5-benzylmercapto-1H-tetrazole was used as a condensing agent, an iodinesolution was used as an oxidant, and a phenoxyacetic acid solution and aN-methylimidazole solution were used as capping solutions. Under theseconditions, the aforementioned nucleic acid monomer compound wascondensed 39 times, the 5′ terminal hydroxyl group was deprotected onthe solid phase, and cleavage from the CPG solid phase carrier anddeprotection of each phosphoric acid site were performed using conc.aqueous ammonia-ethanol mixture (3:1) at 40° C. for 4 hr. Thethus-obtained reaction mixture was concentrated under reduced pressureand reacted in a solution of 1M tetrabutylammoniumfluoride in DMSOcontaining 0.67% nitromethane at 30° C. for 4 hr to deprotect the2′-position hydroxyl group. Ethanol was added to the thus-obtainedsolution to allow precipitation, and the precipitate was dissolved inwater for injection to give an aqueous solution containing the objectcompound (uridine 40-mer).

The analysis results of the uridine 40-mer obtained above by HPLC areshown in FIG. 1. As shown in the Figure, since an almost single sharppeak was obtained, it was suggested that the object 40-mer was obtainedwith high purity. The purity of the uridine 40-mer calculated based onthe peak intensity of FIG. 1 was 74.64% (mass ratio) as shown in theFigure. In addition, the main peak part was separated and purified byHPLC and analyzed again by HPLC. The results are shown in FIG. 2. Asshown in the Figure, since the peak intensity of the impurity furtherdecreased as compared to FIG. 1, it was suggested that the purity of theobject 40-mer became higher. The purity of the uridine 40-mer calculatedbased on the peak intensity in FIG. 2 was 99.61% (mass ratio) as shownin the Figure. In addition, the results of the mass spectrometry (massspectrum chart) of this reaction mixture are shown in FIG. 3. As shownin the Figure, the molecular ion peak of molecular weight 12184.52 wasobserved. Since this molecular weight matched well with the calculatedvalue (12184.66) of the molecular weight of the object uridine 40-mer(U40mer), it was confirmed that the object uridine 40-mer (U40mer) wasobtained.

The HPLC analysis of the uridine 40-mer (U40mer) was performed using aninstrument (HPLC system) of SHIMADZU CORPORATION, and the massspectrometry was performed using an instrument of Waters (SYNAPT G2(trade name)). Furthermore, oligomer synthesis using cytidine EMMamidite (1C^(Ac)) (or (1014)), adenosine EMM amidite)(1A^(Ac)) orguanosine EMM amidite (1G^(Pac)) could also be performed in the samemanner as in the synthesis of the uridine 40-mer (U40mer).

Example 7 Synthesis of RNA Using 4 Kinds of EMM Amidites

Using 4 kinds of EMM amidites of the uridine EMM amidite (1009)synthesized in Example 2, the cytidine EMM amidite (1014) synthesized inExample 3, the adenosine EMM amidite (1019) synthesized in Example 4,and the guanosine EMM amidite (1024) synthesized in Example 5, RNAsshown by the following SEQ ID NOs: 2-4 were synthesized.

(SEQ ID NO: 2) 5′-AUACUAUUCGACACGCGAAGUUCCCCACACCGGAACUUCGCGUGUCGAAUAGUAUUCUUCGG- 3′(SEQ ID NO: 3) 5′-AGCAGCUGUACAUUGACUUUAGCCCCACACCGGCUAAAGUCAAUGUACAGCUGCUUCUUCGG- 3′(SEQ ID NO: 4) 5′-CUUCGCGUGUCGAAUAGUAUU-3′

In the same manner as in Example 6 except that 4 kinds of the EMMamidites of the uridine EMM amidite (1009), cytidine EMM amidite (1014),adenosine EMM amidite (1019) and guanosine EMM amidite (1024) were usedas nucleic acid monomer compounds, synthesis in this Example wasperformed. More specifically, instead of the 39 times of condensation ofthe uridine EMM amidite (1009), the aforementioned 4 kinds of the EMMamidites were condensed from the 3′ side to the 5′ side in given numberof times (61 times in the syntheses of SEQ ID NOs: 2 and 3, 20 times inthe synthesis of SEQ ID NO: 4) according to any of SEQ ID NOs: 2-4. Allconditions other than this were the same as those in Example 6.

RNAs of SEQ ID NOs: 2-4 synthesized in the above were each analyzed byHPLC. As a result, a mostly single, sharp peak was obtained in all ofthem. This suggests that the object RNAs of SEQ ID NOs: 2-4 wereobtained with high purity. The analysis results of the aforementionedHPLC are shown in more detail in the following.

The purity of the RNA of SEQ ID NO: 2 synthesized above was calculatedbased on the peak intensity ratio of the aforementioned HPLC and foundto be 84.27% (mass ratio). This numerical value shows the synthesisyield of EMM amidite subjected to 61 times of condensation reaction.That is, the synthesis yield of a single condensation reaction was ashigh as about 99.72% (mass ratio). According to the mass spectrometry ofthe reaction mixture, a molecular ion peak of the molecular weight of19756.13 was observed. This molecular weight matched well with thecalculated value (19755.71) of the molecular weight of RNA shown by SEQID NO: 2. Therefrom it was confirmed that the object RNA of SEQ ID NO: 2was obtained. Furthermore, the main peak part of the aforementioned HPLCwas separated and purified and analyzed again by HPLC. As a result,since the peak intensity of the impurity further decreased, it wassuggested that the purity of the object RNA of SEQ ID NO: 2 becamehigher. The purity of the RNA of SEQ ID NO: 2 calculated based on thepeak intensity ratio after the aforementioned separation andpurification of the main peak was 96.47% (mass ratio).

Moreover, the purity of the RNA of SEQ ID NO: 3 synthesized above wascalculated based on the peak intensity ratio of the aforementioned HPLCand found to be 79.65% (mass ratio). This numerical value shows thesynthesis yield of EMM amidite subjected to 61 times of condensationreaction. That is, the synthesis yield of a single condensation reactionwas as high as about 99.63% (mass ratio). According to the massspectrometry of the reaction mixture, a molecular ion peak of themolecular weight of 19755.70 was observed. This molecular weight matchedwell with the calculated value (19755.71) of the molecular weight of RNAshown by SEQ ID NO: 3. Therefrom it was confirmed that the object RNA ofSEQ ID NO: 3 was obtained. Furthermore, the main peak part of theaforementioned HPLC was separated and purified and analyzed again byHPLC. As a result, since the peak intensity of the impurity furtherdecreased. The purity of the RNA of SEQ ID NO: 3 calculated based on thepeak intensity ratio after the aforementioned separation andpurification of the main peak was 95.37% (mass ratio), and the puritywas higher than that before the aforementioned separation andpurification of the main peak.

Moreover, the purity of the RNA of SEQ ID NO: 4 synthesized above wascalculated based on the peak intensity ratio of the aforementioned HPLCand found to be 86.67% (mass ratio). According to the mass spectrometryof the reaction mixture, a molecular ion peak of the molecular weight of6650.69 was observed. This molecular weight matched well with thecalculated value (6650.94) of the molecular weight of RNA shown by SEQID NO: 4. Therefrom it was confirmed that the object RNA of SEQ ID NO: 4was obtained. Furthermore, the main peak part was separated and purifiedby HPLC. As a result, the RNA of SEQ ID NO: 4 could be obtained withstill higher purity.

As mentioned above, according to this Example, it was confirmed that RNAof any sequence can be synthesized using plural kinds of EMM amiditecorresponding to plural kinds of bases. The measurement devices used forHPLC and MS were the same as those in Example 6.

While the present invention has been explained by referring to theembodiments, the present invention is not limited by the above-mentionedembodiments. The constitution and detail of the present invention can bevariously changed within the scope of the present invention as long asthose of ordinary skill in the art can understand.

This application is based on a patent application No. 2011-184196 filedin Japan (filing date: Aug. 25, 2011), the contents of which areincorporated in full herein.

INDUSTRIAL APPLICABILITY

As explained above, according to the glycoside compound, the productionmethod of thioether, ether, the production method of ether, and theproduction method of the glycoside compound of the present invention, aphosphoramidite, which can be produced at a low cost and can produce anucleic acid in a high yield and with high purity can be provided. Inaddition, according to the production method of a nucleic acid of thepresent invention, a nucleic acid can be produced in a high yield andwith high purity using the aforementioned phosphoramidite. The use ofthe aforementioned thioether, ether, glycoside compound, and nucleicacid produced by the present invention is not particularly limited, andthey can be used for a wide range of use. According to the presentinvention, for example, they can be preferably used as pharmaceuticalproducts or synthesis intermediates therefor, since they can be obtainedat a low cost, in a high yield, with high purity.

The invention claimed is:
 1. A glycoside compound represented by thefollowing chemical formula (1), an enantiomer thereof, or a saltthereof:

in the aforementioned chemical formula (1), B is an atomic group havinga nucleic acid base skeleton, and optionally having a protecting group,R¹ and R² are each a hydrogen atom or a protecting group, or R¹ and R²in conjunction optionally form an atomic group represented by thefollowing chemical formula (R¹R²A) or (R¹R²B),

respective R^(1a) may be the same or different and each is a hydrogenatom, a straight chain or branched alkyl group, or a straight chain orbranched alkoxy group, R³ is a group represented by the followingchemical formula (R³),

in the aforementioned chemical formula (R³), L¹ is an ethylene group(—CH₂CH₂—), wherein hydrogen atoms besides a hydrogen atom bonded to theα-position relative to [D¹] are optionally substituted by a straightchain or branched alkyl group, n is a positive integer, and [D¹] is anelectron-withdrawing group.
 2. The glycoside compound according to claim1, wherein, in the aforementioned chemical formula (1), [D¹] is a cyanogroup, a nitro group, an alkylsulfonyl group, halogen, an arylsulfonylgroup, or a trihalomethyl group, an enantiomer thereof, or a saltthereof.
 3. The glycoside compound according to claim 1, wherein, in theaforementioned chemical formula (1), L¹ is an unsubstituted ethylenegroup (—CH₂CH₂—), an enantiomer thereof, or a salt thereof.
 4. Theglycoside compound according to claim 1, wherein, in the aforementionedchemical formula (1), n is within the range of 1-30, an enantiomerthereof, or a salt thereof.
 5. The glycoside compound according to claim1, wherein, in the aforementioned chemical formula (1), R¹ is a hydrogenatom, or a substituent represented by any of the following chemicalformulas (R¹A), (R¹B), (R¹C) and (R¹D), an enantiomer thereof, or a saltthereof:

in the aforementioned chemical formula (R¹A), R¹¹-R¹³ may be the same ordifferent and each is a straight chain or branched alkoxy group, or astraight chain or branched alkyl group, or absent, R¹¹-R¹³ are, whenthey are present, respectively present singly or in plurality, and whenpresent in plurality, they may be the same or different, in theaforementioned chemical formula (R¹B), R¹⁴-R¹⁶ may be the same ordifferent and each is a hydrogen atom, a straight chain or branchedalkyl group, or a straight chain or branched alkoxy group, in theaforementioned chemical formula (R¹C), R¹⁷-R¹⁹ are each a hydrogen atom,halogen, a hydrocarbon group, a straight chain or branched alkyl group,a straight chain or branched alkenyl group, a straight chain or branchedalkynyl group, a straight chain or branched haloalkyl group, an arylgroup, a heteroaryl group, a straight chain or branched arylalkyl group,a cycloalkyl group, a cycloalkenyl group, a straight chain or branchedcycloalkylalkyl group, a straight chain or branched cyclylalkyl group, astraight chain or branched hydroxyalkyl group, a straight chain orbranched alkoxyalkyl group, a straight chain or branched aminoalkylgroup, a straight chain or branched heterocyclylalkenyl group, astraight chain or branched heterocyclylalkyl group, a straight chain orbranched heteroarylalkyl group, a silyl group, a silyloxyalkyl group, amono-, di- or trialkylsilyl group, or a mono-, di- ortrialkylsilyloxyalkyl group, which may be the same or different, in theaforementioned chemical formula (R¹D), R²⁰-R²² may be the same ordifferent and each is a hydrogen atom, or a straight chain or branchedalkyl group.
 6. The glycoside compound according to claim 1, wherein, inthe aforementioned chemical formula (1), R¹ is a hydrogen atom, or asubstituent represented by the following chemical formula (R¹Aa),(R¹Ba), (R¹Ca), (R¹Cb), or (R¹Da), an enantiomer thereof, or a saltthereof:


7. The glycoside compound according to claim 1, wherein, in theaforementioned chemical formula (1), R¹ and R² in conjunction form anatomic group represented by the aforementioned chemical formula (R¹R²A)or (R¹R²B), in the aforementioned chemical formula (R¹R²A) and (R¹R²B),R^(1a) may be the same or different and each is a hydrogen atom, astraight chain or branched alkyl group, or a straight chain or branchedalkoxy group, an enantiomer thereof, or a salt thereof.
 8. The glycosidecompound according to claim 1, wherein the glycoside compoundrepresented by the aforementioned chemical formula (1) is the glycosidecompound represented by the aforementioned chemical formula (2), anenantiomer thereof, or a salt thereof:

in the aforementioned chemical formula (2), B, R¹ and R³ are as definedfor the aforementioned chemical formula (1), provided that R¹ is aprotecting group, R^(2a) and R^(2b) may be the same or different andeach is a hydrogen atom or any substituent, or R^(2a) and R^(2b)optionally form a nonaromatic ring, in conjunction with a nitrogen atomto which they are bonded, the aforementioned nonaromatic ring optionallyhas a nitrogen atom, an oxygen atom or a sulfur atom, besides theaforementioned nitrogen atom, and optionally has a substituent, andR^(2c) is a hydrogen atom, an electron-withdrawing group or anysubstituent, which may be optionally substituted by anelectron-withdrawing group [D²].
 9. The glycoside compound according toclaim 8, wherein, in the aforementioned chemical formula (2), R^(2a) andR^(2b) are each a hydrogen atom, halogen, a hydrocarbon group, astraight chain or branched alkyl group, a straight chain or branchedalkenyl group, a straight chain or branched alkynyl group, a straightchain or branched haloalkyl group, an aryl group, a heteroaryl group, astraight chain or branched arylalkyl group, a cycloalkyl group, acycloalkenyl group, a straight chain or branched cycloalkylalkyl group,a straight chain or branched cyclylalkyl group, a straight chain orbranched hydroxyalkyl group, a straight chain or branched alkoxyalkylgroup, a straight chain or branched aminoalkyl group, a straight chainor branched heterocyclylalkenyl group, a straight chain or branchedheterocyclylalkyl group, a straight chain or branched heteroarylalkylgroup, a silyl group, a silyloxyalkyl group, a mono-, di- ortrialkylsilyl group, or a mono-, di- or trialkylsilyloxyalkyl group,which is optionally further substituted or not substituted by anelectron-withdrawing group, or R^(2a) and R^(2b) may form, inconjunction with the nitrogen atom bonded thereto, a 5- or 6-memberednonaromatic ring, wherein the aforementioned nonaromatic ring may or maynot have a nitrogen atom, an oxygen atom or a sulfur atom besides theaforementioned nitrogen atom, and may or may not further have asubstituent, an enantiomer thereof, or a salt thereof.
 10. The glycosidecompound according to claim 8, wherein, in the aforementioned chemicalformula (2), R^(2a) and R^(2b) are each a methyl group, an ethyl group,an isopropyl group, or a t-butyl group, or R^(2a) and R^(2b) form, inconjunction with a nitrogen atom bonded thereto, a piperidyl group, amorpholino group, a pyrrolidyl group, a thiomorpholino group, or othernitrogen-containing alicyclic group, an enantiomer thereof, or a saltthereof.
 11. The glycoside compound according to claim 8, wherein, inthe aforementioned chemical formula (2), R^(2c) is a hydrogen atom,halogen, a hydrocarbon group, a straight chain or branched alkyl group,a straight chain or branched alkenyl group, a straight chain or branchedalkynyl group, a straight chain or branched haloalkyl group, an arylgroup, a heteroaryl group, a straight chain or branched arylalkyl group,a cycloalkyl group, a cycloalkenyl group, a straight chain or branchedcycloalkylalkyl group, a straight chain or branched cyclylalkyl group, astraight chain or branched hydroxyalkyl group, a straight chain orbranched alkoxyalkyl group, a straight chain or branched aminoalkylgroup, a straight chain or branched heterocyclylalkenyl group, astraight chain or branched heterocyclylalkyl group, a straight chain orbranched heteroarylalkyl group, a silyl group, a silyloxyalkyl group, amono-, di- or trialkylsilyl group, or a mono-, di- ortrialkylsilyloxyalkyl group, and further preferably may or may not besubstituted by an electron-withdrawing group [D²], an enantiomerthereof, or a salt thereof.
 12. The glycoside compound according toclaim 8, wherein, in the aforementioned chemical formula (2), R^(2c) isa straight chain or branched alkyl group substituted by anelectron-withdrawing group [D²], an enantiomer thereof, or a saltthereof.
 13. The glycoside compound according to claim 8, wherein, inthe aforementioned chemical formula (2), the aforementionedelectron-withdrawing group [D²] for R^(2c) is a cyano group, a nitrogroup, an alkylsulfonyl group, halogen, an arylsulfonyl group, or atrihalomethyl group, an enantiomer thereof, or a salt thereof.
 14. Theglycoside compound according to claim 8, wherein, in the aforementionedchemical formula (2), R^(2c) is particularly preferably an alkenyl groupor an ethynyl group, or form, together with [D²], a cyanoethyl groupsubstituted by an electron-withdrawing group [D²], an enantiomerthereof, or a salt thereof.
 15. The glycoside compound according claim1, wherein the glycoside compound represented by the aforementionedchemical formula (1) is the glycoside compound represented by thefollowing chemical formula (3):

in the aforementioned chemical formula (3), B and n are as defined forthe aforementioned chemical formula (1), and DMTr is a4,4′-dimethoxy(triphenylmethyl) group, an enantiomer thereof, or a saltthereof.
 16. The glycoside compound according to claim 1, wherein theglycoside compound represented by the aforementioned chemical formula(1) is a glycoside compound represented by the following chemicalformula (1A^(Ac)), (1C^(Ac)), (1G^(Pac)) or (1U):

in the aforementioned chemical formulas (1A^(Ac)), (1C^(Ac)), (1G^(Pac))and (1U), n is as defined for the aforementioned chemical formula (1),an enantiomer thereof, or a salt thereof.
 17. The glycoside compoundaccording to claim 1, wherein, in the aforementioned chemical formula(1), n=1, an enantiomer thereof, or a salt thereof.
 18. A method ofproducing the glycoside compound according to claim 1, an enantiomerthereof, or a salt thereof, which comprises a coupling step including acoupling reaction of a glycoside compound represented by the followingchemical formula (107) and an ether represented by the followingchemical formula (106), in the presence of a halogenating agent and aLewis acid to give a glycoside compound represented by the followingchemical formula (1a), wherein the glycoside compound represented by thefollowing chemical formula (1a) is the glycoside compound which is aglycoside compound wherein R¹ and R² in said chemical formula (1) inconjunction form an atomic group represented by said chemical formula(R¹R²A) or (R¹R²B),

in said chemical formulas (107) and (1a), L² is an atomic grouprepresented by said chemical formula (R¹R²A) or (R¹R²B), B is as definedfor said chemical formula (1), in said chemical formula (106), R⁴ is ahydrocarbon group, a straight chain or branched alkyl group, a straightchain or branched alkenyl group, a straight chain or branched alkynylgroup, an aryl group, a straight chain or branched arylalkyl group, acycloalkyl group, a cycloalkenyl group, a straight chain or branchedcycloalkylalkyl group, a straight chain or branched cyclylalkyl group,or a straight chain or branched alkoxyalkyl group, and in said chemicalformulas (106) and (1a), L¹, n and [D¹] are as defined for said chemicalformula (1).
 19. The production method according to claim 18, furthercomprising a deprotection step for removing said atomic group L² fromthe glycoside compound represented by said chemical formula (1a) toproduce glycoside compound represented by the following chemical formula(1b), and the glycoside compound represented by the following chemicalformula (1b) is a glycoside compound of said chemical formula (1)wherein R¹ and R² are hydrogen atoms:

in said chemical formula (1b), B, L¹, n and [D¹] are as defined for saidchemical formula (1).
 20. The production method according to claim 19,further comprising an introduction step of a protecting group forintroducing protecting groups R¹ and R² into said chemical formula (1b)to produce glycoside compound represented by the following chemicalformula (1c), and the glycoside compound represented by the followingchemical formula (1c) is a glycoside compound of said chemical formula(1) wherein R¹ and R² are except for hydrogen atoms, said chemicalformulas (R¹R²A) and (R¹R²B):

in said chemical formula (1c), R¹ and R² are R¹ and R² in said chemicalformula (1) but excluding a hydrogen atom and said chemical formulas(R¹R²A) and (R¹R²B), and B, L¹, n and [D¹] are as defined for saidchemical formula (1).
 21. A method of producing a nucleic acidcomprising a structure represented by the following chemical formula(I),

wherein B is an atomic group having a nucleic acid base skeleton, andoptionally having a protecting group, R¹⁰⁰ is a hydrogen atom or ahydroxyl group, wherein each respective B may be the same or different,each respective R¹⁰⁰ may be the same or different, and m is a positiveinteger comprising condensing the glycoside compound of chemical formula(2) according to claim 8 to form the nucleic acid comprising thestructure represented by chemical formula (I).
 22. The production methodaccording to claim 21, wherein, in said chemical formula (I), each R¹⁰⁰is a hydroxyl group.
 23. The production method according to claim 21,wherein, in said chemical formula (I), each R¹⁰⁰ is a hydrogen atom, andfurther comprising a reverse transcription step for producing a nucleicacid represented by said chemical formula (I) from a nucleic acidobtained by said condensation step by reverse transcription.